Tire Damage

I am interested in receiving some information about the negative effects of ultraviolet rays causing damage to the tires on my fifth wheel trailer. Why are RV tires so susceptible to damage from the sun when the tires on my truck don’t seem to be affected?
What are the facts?
Murray (Alberta, Calgary)

Murray, the damage caused by ultraviolet (UV) radiation as well as exposure to the ozone virtually effects all tires. RV tires in general are more susceptible to this type of damage since they are considered a slow wearing tire. RV tires typically are not driven as far or as often as regular automobile tires. 

A symptom of ozone or UV damage is the evidence of cracking or “weather-checking” around the sidewall. Ozone is simply a gas that is in the atmosphere. A mutant of sorts, ozone consists of an extra oxygen molecule which is easily attracted to the oxygen in the air and just as easily attaches itself to other oxygen-related compounds such as water and carbon monoxide. The biggest detriment is that it virtually attacks the rubber in the tires and causes brittleness and a lack of pliability. The big disadvantage – ozone-produced cracks cannot be repaired or restored. The tire must be replaced. 

One of the ways tire manufacturers combat ozone is by blending ozone resistant rubber compounds during the making of the tire. These special waxes form a protective barrier against the ozone, but in order to be effective, the waxes must be constantly brought to the surface of the tire. During the flexing and moving of a tire while driving, a fresh layer of combative waxes is kept at the surface. Dormant tires on stored vehicles do not receive enough “exercise” to allow the waxes to migrate to the surface and the ozone has a virtual picnic on any exposed area.

Ultraviolet light (UV), on the other hand, is produced by the sun and travels in the air as solar radiation. An invisible light, UV is harmful to all rubber, plastics, fiberglass, etc., all of which are common to RVs. The effect of unprotected UV exposure on rubber is similar to that of ozone damage – cracking, discoloration and lack of physical mechanical properties. Like the ozone war, tire makers use a carbon substance to combat the effects of UV radiation. Carbon black is an UV stabilizer that actually absorbs the damaging rays and converts them to a simple heat by-product. The carbon substance will eventually lose its ability to protect against the never-ending assault of the UV rays. Contrary to what some suppliers may say, there is no such thing as a permanent UV protector. Here are a few ideas suggested by virtually every tire manufacturer;

1. Keep RV tires clean. Avoid heavy buildups of mud, sand or dirt. Dirt on tires may act as an abrasive of sorts that could inhibit the natural wax protection achieved through normal tire flexing. Also, regular washings with mild, soapy water and a soft brush can remove significant amounts of ozone, especially if you are located in a higher-than-normal ozone area.

2. Inspect the tires regularly.

3. Inflate the tires to the exact requirement based on the actual weight at that tire position.

4. During short periods of non-use, keep the tires completely covered. When possible, remove and store the tires completely out of the sun and temperature extremes.

5. Regularly apply a non-petroleum-based preservative to all surface areas of each tire.

By following these simple guidelines, most RV tires will provide many miles of safe travel.

Vapor Lock

I bought a used Dodge-powered RV with 27,000 miles. My son and I have been repairing things that have happened to it over the years. It was used in California for awhile, then to Phoenix for years and sat out in the sun.
The engine appears fine but on a trial run a transmission seal gave out. We had it repaired and the tranny rebuilt. Recently we were going to a racing meet where the temperature was ninety-three degrees. Eight miles down the interstate the engine started cutting out, but we finally limped home. A serviceman said it was undoubtedly the fuel pump vaporlocking and that it was normal for RVs in hot weather. He said to put an electric fuel pump in it. Is this problem solved by installing an electric fuel pump? Another fellow also told us that lousy gas diluted with alcohol also causes vapor lock. He said to add five gallons of diesel fuel to our forty gallons of gas. He said it will smoke a little, but will get you out of troubles. I also have a kit of a woven insulating material to cover the metal line from the fuel pump to the carburetor to insulate against the heat. We are also putting in a new fuel pump, since it has been setting dry for a long period. I also thought about installing a windshield washer which sprays the front of the radiator to help cool it. We just don't want to get trapped on the interstate this summer if we can help it, so will appreciate any tips!
Dr. Ron, (Niwot, CO)

Dr. Ron, indeed adding an electric, pusher-type auxiliary pump will help rectify vapor lock problems on most older Dodge chassis motorhomes. Installing the pump as close to the tank as possible usually provides the optimum performance. 

Insulating the fuel line, as you suggest, is also a worthy practice, but consider instead going to a larger size fuel line the entire length of the run. Some OEM applications found the original 5/16" fuel tubes mounted inside the frame rails close to exhaust components which simply amplified the problem. Installing 3/8" fuel lines and mounting them on the outside of the frame rails will help tremendously.

It is also advised to replace all rubber hose sections found in the fuel line including the hoses at the tank takeoff tube and all vapor return lines. Since the RV sat for so long and you have already experienced rubber seal deterioration, it's a sure bet all rubber products have deteriorated to some degree. 

Aside from vapor lock, you may be suffering from fuel starvation; literally sucking air through cracks in the rubber sections. Look closely, there are quite a few rubber sections in the system. Normally I shy away from backyard mechanic tricks like adding diesel fuel to the gasoline. Aftermarket products exist that would be a much better choice. And unless you are experiencing extreme overheating there is no viable benefit to spraying water onto the radiator.

No Main Burner in Oven

I have a motorhome with an older Magic Chef LP range. The oven pilot lights and stays on and gets brighter and higher when you turn up the thermostat, but the burner in the oven never lights.
I have checked everything I can think of. I would appreciate any troubleshooting tips you might have.
Gerry (Bryan, TX)

Gerry, assuming the LP pressure is set correctly at 11.0 inches of water column and the unit is relatively clean, here’s what should happen. When you set the oven thermostat to a desired cooking temperature, the standing pilot flame becomes slightly larger, which you have noticed, and begins to heat a thermal bulb attached to a component called the safety valve. This thermal bulb, which is filled with mercury on the older units, expands a bellows in the safety valve and allows the main burner gas to flow from the thermostat to the safety valve and then on to the main burner. As the secondary flame becomes larger, be sure it fully engulfs the thermal bulb. The positioning of the thermal bulb in the secondary pilot flame is crucial. It has to be directly in the fire in order to boil the mercury inside. If it is indeed fully engulfed, the safety valve is probably faulty and needs replacing. Safety valve replacement requires removing the range to gain access to it. And since it can sometimes be a tricky replacement, this one might be best left to the professional technician.

Level for Refrigeration's Sake

I have a Class A motorhome and I often find it challenging to level my rig in some campsites. Is it really that important that the unit is level? I know it was important for the older refrigerators, but with the new ones is it still critical?
Also, if it does cause damage running off-level, is it less critical if I am running the refrigerator on electric as opposed to gas?
James (Watsonville, CA)

James, keep in mind that the force which moves the liquid contents throughout the refrigerator cooling unit is nothing more than gravity. From the point where liquid is first produced in the condenser section until the liquid reaches the boiler section, gravity is employed. Since liquids cannot flow uphill, the importance of running the refrigerator only while level is fully appreciated. 

The crucial section is the low temperature evaporator located within the freezer compartment. To the refrigerator, it matters not how level the galley countertop is, or the dinette table, or the outside corners of the RV. If it does not correspond with the low temperature evaporator coils located in the freezer compartment, all leveling efforts will be for naught. With repeated operation out of level, damage to the cooling unit is inevitable. Leveling is important during any operational mode (12-volts DC, 120-volts AC, or LP) while the RV is parked. While driving or physically moving down the road, there is enough jostling and movement to keep the liquids safely flowing through the system. It is only crucial when the vehicle is not in motion. 

True, today's absorption refrigerators are more forgiving than earlier predecessors, still all RVers should make every effort to completely level the refrigerator. To risk any operation out of level could be an expensive wager indeed. See the photo above for a bunch of reasons to take the time to level the refrigerator properly.

No Furnace Ignition

I need advice on how to fix a furnace. I have a Suburban 24,000 BTU furnace that won’t do anything when called on by the thermostat. I can’t hear the gas being called on or even the blower. I am sure I have checked all of the fuses. Everything else is working fine, stove, refrigerator, oven and air conditioner. The furnace is in an Itasca.
Robert, (Garden Grove, CA)

Robert, first thing to check is the voltage at the furnace. Be sure you have adequate voltage at the furnace itself. Likewise, be sure the ground connection is secure. Next, at the furnace also, disconnect both blue wires going to the wall thermostat and short them together. If the furnace now ignites, you have a faulty thermostat or a broken wire leading to it. 

If still no action, leave the thermostat wires shorted together and check for voltage at the printed circuit board. If voltage is present going into the board, it is probably a failed circuit board. The board can be bench tested to determine if it is faulty. Most professional repair facilities will have the board tester. It's also possible the relay in the furnace could be faulty, but we would need the schematic or wiring diagram to fully evaluate that possibility. My guess, though, is that you are experiencing either a voltage/ground problem, (hopefully), or the board is faulty, (hopefully not).

P&T Relief Valve Questioned

I have a two year old travel trailer. Recently, the pressure relief valve on the hot water tank began dripping regularly. The water appears to be over-temperature. What is my problem? Could it be the thermostat? Can I fix it myself?
S. Farmer, (e-mail)

Steve, though a faulty thermostat may be the cause of your symptoms, I would first look closely at the pressure/temperature relief valve itself. The P&T relief valve is an interesting device. Contrary to what some may believe, this valve will normally drip some water during each and every heating cycle. Here’s why. As any containerized liquid is heated, that liquid will expand causing not only a rise in temperature, but also a rise in pressure, (a percolator effect, if you will).

Since the RV water heater is a tank filled with water, if there were no method to absorb or control this expansion during the heating cycle, the unchecked pressures and temperature could rupture the tank resulting in serious injury. Temperatures below 210-degrees Fahrenheit are considered relatively safe. Therefore, all P&T valves on today’s water heaters are pre-set (non-adjustable) to open at 210-degrees F.

In the small confines of the RV water heater, the water is heated very quickly with a rather inordinately large LP burner flame, so keeping up with the drastic fluctuations of both temperature and pressure is no easy task. Additionally, in RV water heaters there is usually a cushion of air at the very top above the water level that acts as an accumulator and buffers the water. It also allows space for the water to expand into while being heated. This air (oxygen), is eventually absorbed into the oxygen portion of the water. At this point there is no place for the expanding water to move into since the tank is literally completely full. The P&T valve then does its job of becoming a virtual hot water faucet – it opens. Expelling hot water from the outlet of the valve allows more cold water to enter the tank (lowering the temperature) and the valve snaps shut.

Usually, draining some water from the water heater tank will reinstate this cushion of air if excessive dripping is encountered. The fact that this dripping of the relief valve seems to be more prevalent today is attributable to the design of the modern water heater. Back in the good ol’ days all water heaters were thermostatically controlled manually. Today, with the prominence of electronic ignition, manual control of the temperature of the water is taken away. On many units the thermostat is a pre-set thermal switch which electrically turns off the heating sequence when the pre-set temperature has been reached.

There will continue to be P&T valves that simply fail over time, but by and large all will drip occasionally. They must, however, drip only during the heating cycle. If indeed they drip or weep during non-heating phases and the pressure within the fresh water system is less than 150 PSI, then the relief valve may indeed be faulty. The P&T valve is easily replaced, though it may take a special tool. And it is relatively inexpensive, considering. All well-stocked RV part stores will carry them.

Window Removal

How do you remove the RV windows so they can be re-sealed on a Southwind Class A motorhome. The coach is 27-feet long.
Dave, (Mobile, AL)

Dave, from inside the RV, remove all the screws around the inner frame – also called the trim garnish (see photo). The window is not really screwed to the wall of the RV. The sidewall is actually "sandwiched" between the outside window flange and the inside garnish trim. Take care when removing these Philips-head screws. Avoid using an electric or pneumatic screwgun since it is easy to strip the head.

After the inside aluminum trim is removed, carefully apply outward pressure to the edges of the window frame while a partner holds onto the window from outside and slides a flat putty knife along and under the exterior flange. Eventually the window will push all the way out. Be sure to remove absolutely all the old sealant and clean both the outside of the rough opening in the sidewall as well as the back side of the flange around the window. Use a good quality butyl caulk or putty tape (I recommend Eternabond tape), and apply more than enough to the flange so when the window is reinstalled it will squeeze out around the entire perimeter of the frame.

Insert the window into the opening and be sure to "center" the window vertically and horizontally; use shims to raise the assembly if necessary. Tighten the screws through the inside trim in a cross pattern much like you would tighten a wheel assembly. Avoid gaps in the sealant that would permit water entry. Next, carefully trim away the excess and apply a very thin bead of clear silicone across the top and around the upper radiused corners of the window. Smooth out this bead of silicone by wetting your finger and carefully sliding it over the sealant. Avoid rain or washing the coach for 24-hours.

Weak or Faulty GFCI

I have a class A motorhome bought used. It is in nice shape except for one problem. When I plug the power line into a GFI plug, it trips the connection. The RV has a GFI in the bathroom that seems to be working. Got any ideas?
J. Wimbish, (Arlington, WA)
  
John, the problem could be located either in your RV or in the park wiring. It is important to know if the same GFCI, (ground fault circuit interrupter), on that pedestal trips when another RV is connected to it, or is it just yours? Also, is it possible for you to try another GFCI-equipped pedestal? Perhaps at another site? It is quite possible that single GFCI is weak or faulty, but it's also possible the entire park is miswired.

Here's what you can do; With the RV plugged into a source of 120-volts, check each receptacle in the coach with a voltmeter and a polarity tester. You may just find a receptacle with reversed polarity. Also, the GFCI in the RV could be wired incorrectly thereby allowing the "hot" lead to cross over to the neutral bus since both sets of wires connect to the GFCI in the coach.

In addition, with all power removed from the rig, remove the GFCI receptacle in the bathroom and identify each set of wires entering the receptacle box. Note the contacts on the GFCI are labeled, "line" and "load." The incoming black and white wires connect to the "line" terminals and the remaining black and white wires, (the rest of that circuit), connect to the "load" terminals. It may be necessary to electrically activate the system to determine which set is which. I recommend a qualified RV service technician take over at this point.

With the coach plugged in, one set of conductors at the GFCI will indeed be "hot." The technician will use a voltmeter to determine the hot "line" set of wires and their proper connection to the GFCI. If that does not clear the problem, it will be necessary to perform a hi-pot test, also called an insulation breakdown test. When applied to the electrical shoreline cord, the hi-pot test forces high voltage back through the system and reveals if any leg of the circuit is faulty. Further troubleshooting can determine if a particular circuit is at fault or if one wire in that circuit is shorted. It sounds like a visit to your local RV service center may be in order.

Intermittent Levelers

I have problems with my hydraulic leveling jacks not setting > vertical before they start to extend out. It is mostly intermittent since sometimes they operate fine. Where should I look > for this problem? Is it most likely electrical or mechanical? > Last year I disassembled the control box on the dashboard and > renewed the electronic connections by cleaning them and it > seemed to help. I don’t know if it was just a coincidence or > if it really helped. I am well-versed in mechanics and > electronics so am not afraid to tackle a problem that is > curable within the scope of my regular hand tools and meters. > Can you advise? The jacks are about eight years old.
Marvin, (Topeka, KS)

Marvin, it appears you either have a mechanical or possibly a hydraulic problem since the levelers extend as they should some of the time. Or both! Look closely for a pinched hose, a damaged mounting bracket or any binding of the movement throughout the travel of each jack in question. It is also wise to lubricate all the moving pivot points with white lithium grease. There may be a filter in the hydraulic system for those jacks so check to be sure it is not partially clogged. Follow each line from the reservoir to each jack and inspect closely for leaks or kinks. Aside from the mechanical, you may also have fouled fluid in the reservoir. At eight years old, it may be time for fresh fluid!

Leaking Holding Tank

I have Dodge motorhome with a leaking gray water holding tank. I have found several cracks where the hangers hold the tank to the underside of the RV. What is the best method to repair the tank? Charles, (Berryville, AR)

Charles, I'm guessing your tank is mounted with brackets similar to those in the photo at left. I receive a lot of inquiries regarding cracks in plastic tanks; black and gray holding tanks, fresh water holding tank, plastic gasoline tanks, etc. Click here to see my most common response to your question.

(Note: The response to Charles above was edited in the spirit of consolidation for inclusion into the Q&A Archive)

Water Heater Pilot Outage

I have a Nomad 23-1/2 foot trailer. It has a Suburban water heater. The orifice was plugged on the LP pilot. I replaced the pilot unit, but now I can't keep the pilot lit. I even made sure all of the air was out of the lines by lighting the stove at the other end of the trailer. Any suggestions?
Steve, (Longview, WA)

Steve, here are a few things to consider regarding your pilot flame situation. First, has anyone checked the LP pressure lately? For RV appliances to run at their optimum, the system regulator should be set at 11.0 inches of water column. Use of a "U" tube manometer will yield the most accurate results. If the flame goes out as soon as you release the button you may have a faulty thermocouple; provided the thermocouple is correctly positioned in the flame to begin with. Only the tip of the thermocouple, the hot junction, should actually be in the flame. Additionally, the other end should only be one-eighth turn tighter than finger-tight into the control valve. Too tight of a connection here will compress the contact pad and cause insufficient voltage to reach the electromagnet. RV service shops can easily bench test the thermocouple. If the pressure is correct and the thermocouple correctly positioned in the flame, the electromagnet in the gas control valve could be faulty, though this is not usually the most probable cause.

Finally, verify that the correct size orifice was used in the pilot tube. Contact Suburban or your local repair center for the correct size for your model.

Pine Pitch on EPDM

I have just purchased a 33' Shasta 5th wheel trailer with a rubber roof. I am getting a lot of pine pitch on the roof. I used to use denatured alcohol to remove the pitch from my old trailer with a metal roof. I am afraid that maybe the denatured alcohol will soften the rubber roof. What is the best pine pitch remover to use on an EPDM roof.
Richard, (Worcester, MA)

Richard, try this. Realizing that some petroleum products may be harmful to EPDM rubber roofing if it becomes saturated, carefully moisten a clean, soft, cotton cloth with regular mineral spirits and lightly rub the pine sap from the roof. Do not pour the spirits directly onto the roof, but use a clean portion of the cloth each time. Eventually you should be able to remove all of the pine pitch. Though not always 100% necessary, apply an EPDM protectant to the affected area after removing the pine sap. And don't park under that pine tree any more!

Furnace Odor

I have a Duo-therm furnace, model #90130.001 and when the propane tank gets almost empty, the furnace gives off an awful gas odor in the RV. Is there anything one can do to eliminate this odor?
Ned, (Jonesborough, TN)

Ned, the LP odor seemingly emitting from your Duo-Therm furnace when the container is almost empty is not typically attributed to the furnace itself, but rather the level of fuel in the container. A chemical odorant, ethyl mercaptan, is induced into liquid propane during the distilling process to insure that if a leak occurs, the user would indeed be made aware of it.

Liquid propane is inherently odorless and colorless and as potent as LP is, the odorant is added as a safety feature. Since the mercaptan is heavier than the liquid propane, it eventually settles to the bottom of the storage container. When a container is near empty, the percentage of mercaptan relative to the remainder of the liquid fuel is far greater than normal. When LP is utilized in RV appliances as a vapor during this low level situation, some of the odorant can seep into the appliances and become evident to the user.

In furnaces, this phenomenon is usually kept to a minimum since the furnace is a completely sealed system and uses outside air to mix with the LP for combustion. But it can happen since the 900 series Duo-Therm furnace utilizes a different type of burner configuration which forces an extremely rich mixture into the combustion chamber. If any unburned fuel is left inside the chamber at any time during the heating cycle, the smell could be evident inside the RV. You probably do not have a problem as long as you do not smell the mercaptan at other times when the container holds a greater amount of LP. To be sure though, I recommend you have your coach thoroughly leak tested using a manometer.

Waste Plumbing Clearance

My question is concerning the ground clearance for the sewer hose coupler and dump valves. Mine seems to be insufficient. I have had to replace the gray water valve twice and reattach the coupler above the black water valve about three times in the past 18 months. I have thought of skid plates as an option. Also I have thought of using individual drain outlets, but that seems inconvenient. This is a very poor design, the termination point is just forward of the rear bumper and hangs pretty low. It is a mandatory inspection item after every trip. Driveways and dips can be a challenge at times. I have to be very selective of which gas stations I go in and out of. I wrote to the manufacturer about the design problem but never got a reply. Any suggestions or advice would be appreciated. Carlos, (San Diego, CA)

Carlos, indeed some waste system designs can be somewhat lacking, especially when the coach has a long overhang behind the rear axle. The holding tanks, dictated by the floor plan design, are sometimes positioned beyond the rear axle. Here's an idea that just might gain some ground clearance.

Completely empty and flush out each holding tank first. Then remove both the dump valves and all the termination plumbing. Begin by installing the dump valves directly to the tank outlets. Remember that every inch of drain line from the outlet on must drop a half inch or so for every foot of run. With the dump valves attached directly to the tank outlets, the remainder of the assembly will not hang as low.

Then, just like a puzzle, connect the two outlets together as high as possible using a "wye" or sweep "tee" fitting and other ABS fittings. Be sure to "dry fit" all the pieces first. Then, mark their placement and remove them all and cement them back into place. If you cannot reach the valves once they are positioned directly on the tank outlet, consider using electric dump valves instead of the manual type. Check out the Drain Master electric waste valve. Easily installed, they are operated by a simple push of a button.

I do not recommend installing skid plates or bumper casters which only leads to other chassis related ills. Getting the plumbing as high as possible is your best bet. And keep after the manufacturer. They need to be made aware of design discrepancies! Most coach makers welcome such input.

Noisy Water Delivery

What can be done to reduce or eliminate excess noise/vibration when using my self-contained water system? Everything works just fine, but the noise when the pump is being used seems excessive. Will an accumulator help or just reduce the amount of time the pump is working? David, (Texarkana, TX)

David, before jogging down and buying that accumulator, double check the installation of the water pump itself. Be sure the pump housing or motor is not touching a portion of a nearby cabinet or enclosure. Also be sure the rubber mounts are properly isolating the pump from it's mounting position. These items are probably okay, but if your RV is older, it's best to check these items from time to time anyway.

Adding the accumulator will probably be your best bet if the pump is mounted properly. The "hammering" caused by pressure and moving water will certainly be reduced if not totally eliminated. The accumulator provides a needed cushion of air that will absorb the pounding effect you now are experiencing. It will definitely add years to the life of your pump.

Electric Brake Engagement

I have a travel trailer with electric brakes. The problem we are having is with the brakes. The brakes will engage when pulling it even though we do not have the brakes hooked up in the plug-in on the back of the truck. We unhooked the battery on the trailer and currently do not have this problem but it is not safe to tow the trailer without the brakes. What could be the problem?
Tammy, (Laure, TX)

Tammy, all travel trailers equipped with electric brakes must also be outfitted with a device called an emergency break-away switch. The purpose of this switch is to engage the trailer's electric brakes if the tow vehicle and trailer should ever become uncoupled while traveling down the highway. The power for this switch comes from the trailer battery which is why your symptoms disappear when the battery is disconnected.

The switch should be located at or near the tongue of the trailer and consist of box-like device with a pin fully inserted in the switch with a long cable that attaches to the hitch of the tow vehicle. When the pin is pulled, (picture a hand grenade), the switch closes and voltage is allowed to pass to the electric brakes on the trailer. Either your pin has been pulled out or the switch is simply faulty.

Break-away switches are relatively inexpensive and available at any RV accessory store. They should be cleaned and tested from time to time. If the pin and the cable attaching it are missing, a complete new switch should be installed. To test a break-away switch, jack up one side of the trailer and have a partner spin the tires on that side. The tow vehicle does not need to be connected for this test; a healthy trailer battery does, however. While they are spinning, pull the pin from the break-away switch; the brakes should immediately lock up. If they do not, there is an open in that circuit and further troubleshooting is in order. Jack up the opposite side and try the same test.

Cabover Window Leak

I have a 26-foot motorhome in excellent condition except we had a leak in an upper window of cabover that rotted wood in the front and lower section of cabover. Local dealers tell me the cost to repair it is in excess of value of unit and haven't even quoted a repair cost. They only show me their new models. Is this worth repairing? Do I have to depend on dealers who will try to sell me another unit rather than help me fix mine? Is this type of repair more difficult?
Christi, (Litchfield, OH)

Christi, unfortunately, such damage in the cabover section can be quite costly. However, for a dealer to not even quote a repair estimate while trying to steer you to a new vehicle is disingenuous at best. All reputable repair facilities will provide an estimated cost of repair and explain the pro and cons of such a repair. A thorough inspection is required in order to fully evaluate the feasibility of a repair. And keep in mind, not every RV service facility is able to perform this type of repair. I’ve sent you the name of a facility near you; let me know how it works out.

Slow Flow No Go

I have an Innsbruck and all of a sudden water will not flow into the toilet. We do use a filter for all the water coming into the camper. It is a little slow in the sink and shower, too. I did clean the screens at each faucet. What else can I do?
Bill, (Keithville, LA)

Bill, it is quite possible the filtering media in the filter you are using has been saturated beyond its usefulness. Oftentimes filters become clogged and must be replaced with a new insert. Some have replaceable cartridges while some must simply be tossed out and replaced with a complete new filter. Not knowing which filter you are using, I would indeed at least start there.

Does the problem persist whether you are using city water or the on-board system with the pump or both? If the problem exists only when operating the water pump, look for another filter on the input side of the pump between the tank and the pump. Oftentimes, particles inside the water tank can become lodged in the pump filter or in the pump itself. If it happens while on city water also, look for a kink or sharp bend in the supply tubing at or near the city water inlet inside the coach.

It's also quite possible the fresh water line is blocked at the toilet inlet valve or that the valve itself may have been rendered faulty. Try this; with the water source disconnected or turned off, remove the tubing right at the toilet. Have a large pan at the ready then have an accomplice briefly turn the water pump on. If water exits the tubing at the toilet, it would prove a faulty inlet valve on the toilet. 

High Freq Hum

I have an older Bounder diesel pusher and I'm on my second battery charger for the coach batteries. Unfortunately I continue to hear a very large humming noise from the charger. Also, the charger is located just under the bed and this creates quite a problem with sleep. Is this humming normal and if so can it be moved away from ear distance for sleeping? Jack, (Toledo, OH)

Jack, what you are hearing is an audible mechanical resonance created by a harmonic distortion in the converter/charger. I know that sounds like double-speak, but the phenomenon is somewhat technical. I'll try to explain the happenings.

Most AC electrical loads are linear, meaning the current is proportional to the AC voltage. Examples include regular AC lighting and simple motors. Linear devices rarely vary in frequency. Non-linear electrical loads, such as your AC/DC converter, can produce electrical waveforms that are multiples of the normal 60 Hertz sine wave associated with the 120-volt AC electrical system in the RV. These multiple waves, called harmonics, are actually superimposed over the original sine wave. The original, fundamental sine wave combined with any of the overlaying harmonics will result in a non-sinusoidal wave form of an entirely different shape.

This is very similar to the harmonics associated with stringed musical instruments. (I could demonstrate this easier on my guitar!) This new waveform then, has the ability to create a mechanical resonance within the transformer section of the converter. Overheating of the transformer, additionally, can lead to increased levels of harmonic distortion which usually manifests itself as an audible hum via the mechanical resonance. (Hang on, we’re almost there!)

The laminated steel plates that make up the transformer literally begin to vibrate at a frequency that is able to be heard. Unfortunately, there's not much you can do to eliminate this resonance short of redesigning the converter to include special notch filters to block out or eliminate the offending frequencies. Sound baffles can be placed between you and the converter, but care must be taken to avoid any build up of heat in the converter area.

The best cure is to simply upgrade to one of the newer, high frequency converter/chargers like the one pictured above. They are engineered with devices that can cancel out the harmonics and allow the waveform to maintain the 60 Hertz necessary. Another benefit of upgrading is the optimum battery charging abilities available with the sophisticated, smart converter/charger. (Whew!)

Water Heater Mini Explosion

I have a Cobra 24-foot motorhome with a water heater problem. When I turn on the ignitor it explodes when igniting the propane, when it finally does. A loud boom! I can hear the ignitor clicking before it does light. Can you give me some suggestions? It seems to be the worst when it is a little cold outside.
Dan, (Tucson, AZ)

Dan, it’s my hunch your unit may have a partial blockage in the curved mixing tube. Plus, I would venture your water heater is in need of what is commonly referred to as a "clean and service."

All LP appliances require yearly preventive maintenance in order to remain at optimum operating efficiency. Performed each season, this set of specific maintenance procedures will minimize if not virtually eliminate all appliance operation failures. Too lengthy to list comprehensively in the column, some of the steps include setting the incoming LP line pressure, cleaning soot and carbon build-up from probes and sensors and checking/adjusting the appropriate gap spacing.

In addition, cleaning electrical contacts, checking circuit board functions, etc. are all items mandated by virtually all appliance manufacturers.

Specifically, I would have the LP gas pressure at the water heater checked and the adjustment of the primary air shutter. Misalignment of the burner tube could also lead to your symptoms. But I would look close for a blockage of sorts in the burner tube itself, impeding or disrupting the normal flow of incoming LP as it is mixed with the primary air.

Refer Ventless

I have a Tioga Class C. I'm a first time RV owner and hope to travel the Southwest this summer with my family. A friend of mine took it out for a ride and knocked off the top of a vent above the refrigerator. Rain got in for a night (light rain) and I have no idea if it caused any damage. I don't even know what this vent is for? Can you please shed some light? Until I get a replacement, I've covered the hole with plastic and tape. Would appreciate any help.
Harrv, (San Francisco, CA)

Harry, do not operate the refrigerator with that vent opening blocked off! It is vital that the refrigerator have a clear and open chimney from the lower door on the side of the RV behind the refrigerator, all the way up the back of the cooling unit and out through the roof opening. If you operate the refrigerator in this condition you will quite likely melt that plastic and start a fire and possibly do damage to the cooling unit. Heat transfer and heat build-up must exit through that opening. If anything, it is much better to operate the refrigerator with just the hole in the roof than to block the opening completely.

Replacement refrigerator roof vents are readily available at any RV supply store and can be easily installed by any RV handyman. Use plenty of putty tape or Eternabond tape under the flange of the vent base and secure it to the roof with screws sheet metal screws. Add a layer of Eternabond tape over the screw heads and all will be fine. But until then, use an ice chest.

Low Voltage?

I just got a used Alpenlite 5th Wheel. I noticed when I plugged into shore power the outlets all tested at 117-volts versus the 119-120-volts coming in at the extension cord. Is this normal and will it affect the longevity of my appliances?
Jim, (Bothell, WA)

Jim, 117-volts AC is not abnormal on many utility electrical grids, especially in campgrounds. There is also always some voltage drop through all the conductors and devices inside the RV and especially through any extension cord used. But most components are safely operated anywhere in the 103-volt to 125-volt range. Your current voltage poses no threat to your appliances. Keep monitoring the voltage though and if it continues to drop or vary considerably, have an experienced RV technician perform a hi-pot test on the AC system as well as a hot skin test. Oh, be sure any extension cord you use in conjunction with the shoreline power cord be sized correctly!

Something you can do in the meantime; with the voltage disconnected, tighten all the connections at the breaker box inside the coach and double-check any wire nuts in the system. You'll probably find some in the "J" box where the shoreline cord ends inside the RV. Though not mandated by code, I always recommend applying a wrap or three of black electrician's tape around all wire nuts just in case the constant jostling loosens them.

Non-Stop Refer

I have a Class A motorhome and we leave the refrigerator on all the time. Will this shorten the life of the refrigerator?
Walter, (Quitman, MS)

As a general rule, Walter, the more any component or device is used, the quicker it will wear out. Even though there are no moving parts to an absorption refrigerator, constant use may not shorten its life drastically, but it will certainly get there faster. Do you actually use the refrigerator all the time? If you do and you truly need to operate it non-stop, be doubly sure it is level and it has plenty of ventilation at the rear of the refrigerator around the cooling unit. If you operate mostly on LP, be sure to clean and service the burner regularly and have the gas pressure checked at least quarterly. If you do not need it to actually refrigerate food, turn it off and block the door open when not in use.

No Battery Charge Via Converter

I own a Coachman 23-1/2 foot 5th wheel. The RV battery does not take a charge while the unit is plugged in, however it does charge while I am hooked up to my tow vehicle. I have checked all the fuses and wiring that I can trace with no problems found.
Alexander, (Fallon, NV) 

Sounds like it's time to check the converter/charger in your RV, Alexander. The AC side of the converter is either plugged into a receptacle or is wired directly to the 120-volt AC system, always through a circuit breaker. Check the circuit for the converter and be sure that breaker is not tripped. If the breaker is fine, then the problem may be interior to the converter.

Most converters utilize an internal relay that switches to converter power when plugged in and switches back to battery power when disconnected from the shoreline. Relays can become stuck or burned over time and not switch from one source to the other, thereby creating an open in the battery circuit.

Another possibility is a blown fuse in the battery charge circuit itself. A fuse could be situated in the converter or in-line near the battery. Check each of these possibilities. Chances are it will be one of them. If all else fails, send me the make and model of that converter and we’ll dig a little deeper.

Holding Tank-itis

My husband and I recently bought a used 2000 Jayco motorhome. After buying it, we discovered the grey water tank does not seem to drain properly. We immediately contacted the RV service shop that had inspected the unit before we purchased it. They flushed it several times. We took it out for the first time this weekend, used it, and flushed it several times hoping to get rid of anything that may still be blocking the pipe and/or the valve. It seems to come out strong when you first open the valve, but then slows to a trickle, even though the gauge shows it being 2/3 to 1/3 full. Also, the valve seems to leak, so that when you pull the drain cap off, liquid spills out immediately before you can attach the hose. We thought it was just grey water, but when we emptied it today, blue liquid came out, indicating that the black water valve was leaking, too. Also, the gauge for the fresh water tank usually reads empty, even when we have filled it. We have shown this to the RV shop that said the unit worked perfectly. Do you have any advice as to how to proceed with these problems?
Janet, (Sandy, UT)

Janet, welcome to the joys of holding tank-itis. All RVers, at some point during their travels, have experienced much the same dilemmas; either the monitor panel reads inaccurately and/or the termination valves leak - usually all attributable to a lack of maintenance, in your case, by the previous owner.

The RV waste management system, much like LP appliances, the generator, or any other component with moving parts, must be serviced periodically. Of course, there are plenty of examples of mis-engineering out there also. You just may be suffering from a combination of ills. 

It is doubtful the gray water holding tank is plugged or blocked since the contents are liquid. The fact that the monitor panel still indicates some level of waste water is usually indicative of soiled/contaminated probes inside the tank. More common with the black water tank, it can and does happen with the liquid waste water also. Cooking oils, soaps, shampoos and other gunk can actually make an electrical connection of sorts and short across the probes causing an erratic reading. Check out my review of the Horst Miracle Probes here. The addition of these replacement probes will likely eliminate the inaccuracies of the monitor panel.

Also, closer inspection will be necessary to verify the proper drain slope from the outlet fitting at that tank all the way to the termination point where you connect the sewer hose. Obviously water cannot flow uphill, so be sure you have plenty of drop for the entire distance. It will be necessary to remove the termination valves to replace the seals anyway, so carefully rinse and drain as much as you possibly can from each tank. Flush both tanks with fresh water as completely as possible beforehand.

Now might be a good time to upgrade your manually operated termination valves to electric gate valves such as those produced by Drainmaster. Uneven pulling on the slide valve by hand may have damaged the adapters on either side of each valve. Even if you don't upgrade to the Drainmaster, be sure the adapter fittings on each side of both valves line up properly and that the slide mechanism fully opens and closes. Any binding of the fittings and/or the valve and they might not close all the way. 

Lube the seals with Dow 111 grease and carefully tighten the four mounting screws in an even manner. Do not over-tighten. This will indeed warp the adapter fittings. Run the slide open and closed a few times to be sure they are operating properly. If there indeed is some type of blockage in the drain piping from the gray water holding tank, it will be revealed as you disassemble the puzzle of all the ABS fittings and the valve. Obviously, clean or replace any blocked or damaged fitting or pipe.

No Screens Please

Do you have a source for mud dauber or wasp screens for the furnace inlet and outlet vent?
Bill, (Broken Arrow, OK)

Bill, I do not recommend blocking the fresh air inlet tube or the hot exhaust on the RV furnace with any type of screen, as popular as they seem to be. Any air restriction of these components will cause erratic appliance operation and shorten the life of the appliance. I do, however, recommend taping off those openings during winterizing or other periods of storage or non-use to keep the critters out, but during actual RV use you do not want to modify or impair air flow in or out of the unit.

All mud dauber's nests should be checked for and routinely removed during the annual cleaning of the furnace. The photo exemplifies the importance of annual furnace maintenance, but during the actual operation of the furnace, keep those tubes free from any obstructions! Including those screens commonly found in accessory stores.

Draining, but with Difficulty

I have a Wilderness and the bathtub will not drain properly until I open the sewer valve on the outside of the trailer. Does that mean I may have a vacuum problem with the air vent?
Jerry, (Topeka, KS)

Jerry, it sure sounds like the vent pipe has fallen down into the holding tank below the surface of the liquid in that tank. When you open the termination valve, air is allowed in which quickens the draining of the tub. The bad news; it is usually necessary to drop the tank to properly affix the vent pipe to the tank so this may be a task for a pro.

But first, be sure it has indeed fallen. Remove the vent cap on the roof for that tank; many have caps that twist off. If the 1-1/2” ABS drain pipe is not sticking up above the roof line about one to two inches, then it probably has fallen into the tank. Here's a brief overview of how it's done should you want to tackle this yourself. 

Drain and flush both holding tanks. Disconnect the termination assembly so that the gray water tank can be dropped straight down. Remove the panel below the tub and disconnect the "P" trap and the upper portion of the drain line. Locate the suspect vent pipe inside a closet or lavatory cabinet. Cut the vent pipe as close to the floor as possible using a hacksaw. Use a flashlight and a mirror to view the top of the tank from under the chassis and look for any other drains or vents that may enter the top of that tank. All drain pipes must be cut as close to the floor as possible. 

Remove any electrical wires attached to "well nuts," or probes that connect the monitor panel to the tank. Be sure to mark the exact location for any such wires and to note their respective colors. Locate and determine just how the tank is secured to the underside of the RV. Many installations utilize mounting straps or metal bands that completely support the bottom of the tank. Some may have an upper flange that is bolted or screwed to the underside of the coach. Look over the installation carefully to determine which method was used. 

Support the tank with a floor jack and remove all the supporting hardware and carefully lower the tank to the ground. If the existing fitting for the vent pipe is damaged or if a rubber grommet fitting has been used, install a new fitting which will allow you to insert the vent tube into the fitting yet prohibit further movement down into the tank. Reinstall all components and the tank in the reverse order and insert a length of ABS pipe into the new fitting on top of the tank. You can use a new full-length section or use two shorter pieces and connect them with an ABS coupler somewhere convenient under a cabinet or inside a closet. Fill the tank completely with fresh water to test for leaks anywhere in the system. And don't forget to reinstall the vent cap up on the roof.

Low Vac Evac

I would like to know whether I can use my vacuum truck for portable toilets to pump out RV black and gray water holding tanks and will it or could it do any damage to the RV. The vacuum is like that of a septic truck but works at a lower vacuum, about 17 - 25 inches. Do you have any general procedures to follow?
John, (Campbell River, BC, Canada)

Granted John, this isn’t a question I receive very often, but I think I understand why you are asking; you probably want to offer this service at campgrounds or other groupings of RVs. As long as you can make a leak-proof connection from your suction hose to the termination outlet common to all RVs, there should be no reason why you cannot use your low vacuum truck. Twenty-five inches of vacuum should do no harm to any component in the waste holding system. All the plumbing from the tanks to the termination assembly are connected pieces of cemented SCH 40 ABS pipe along with the appropriate fittings. I would, however, avoid connecting the suction hose to any flexible sewer hose for obvious reasons.

(Update: After publication of the above question, I received a few emails regarding my response above. Read my update relating to this RV Doc question here.)

"Smart" Battery Charging

I have a Holiday Rambler travel trailer which the local repair shop says needs a new power converter. Can this replacement job be done easily or should I have the dealer do it?
Steve, (South Bend, IN)

Steve, though some converter installations are relatively easy, especially if the new one is the same brand and model of the one you are replacing, I'd recommend you let a service center perform the replacement. It should take an experienced RV tech no more than an hour to an hour and a half to swap it out. 

But I'd get a second opinion to verify that your existing converter is indeed faulty. It just may have a poor battery charging function. Rarely do converters simply "go bad." Most are fine at converting AC to DC, but are ill-equipped to be an effective battery charger.

If you are serious about RVing, however, you might want to consider adding a multi-stage “smart” battery charger such as the Xantrex Truecharge 40 which uses charging criteria developed specifically for RV use. It optimizes the charging parameters by taking into account the battery temperature, the total amp-hour capacity of the battery bank and the type of electrolyte used. Here's a brief overview of how it operates. 

The multi-stage charge sequence begins with a bulk charge which basically pours all of the converter’s output into the depleted battery bank until the voltage approaches the gassing point, (around 14.2 – 14.4 volts). This bulk stage will bring the battery up to about 75 –80% capacity in the shortest amount of time. 

Next is the absorption stage. In this stage, the battery is charged at 14.4 volts until the current decreases to about 5-amps. At this point the battery bank is considered fully charged. Then it enters a maintenance type of charge sequence called the float stage. This float charge is commonly referred to as a "trickle charge." A constant voltage of about 13.3 to 13.5 volts is applied at a low current of about 1 – 3 amps. This is the point at which most other converters begin to boil the electrolyte. The Truecharge 40 eliminates this fear and most all RVs can be left plugged in indefinitely when equipped with this charger. The exception is when the battery bank consists of true deep cycle batteries such as two Trojan T-105, 6-volt golf cart batteries.

Most true deep cycle batteries are best utilized when charged and discharged deeply between charge cycles. They are not designed for prolonged periods of float charge. The Truecharge 40, however, considers this and allows you to choose a charging cycle sequence that only includes two steps – the bulk charge and absorption charge. A third, constant output voltage mode can also be selected if necessary. 

A fourth, equalization stage is also available. This equalization mode is simply a controlled overcharge designed to minimize or prevent sulfation from occurring in flooded batteries. During normal charge cycles, especially in the hotter climates, higher temperatures and impurities in the electrolyte may prevent some cells from attaining a full charge while allowing a higher degree of sulfating on the plates. Since not all batteries require a regular equalization charge, (most sealed, lead acid batteries in fact, do not), this feature is user-induced rather than automatic. 

Other advantages of the Truecharge include the ability to choose between gel, flooded or AGM battery types. Since each is constructed differently, the charging patterns should also be different. Over-temperature protection, overload protection and reverse polarity protection are additional benefits. And the good news is that it is quite simple to install. The 120-volt circuits of your existing panel will stay intact and only the battery charging function will be switched over to the Xantrex. 

In most every case, an upgrade to one of these highly efficient, "smart" power chargers is a wise investment and may very well eliminate or at least minimize the 12-volt battery charging woes so prevalent today.

Dual Purpose Appliance

I have a 1989 Kit Companion travel trailer with an old Trav'ler Duette stove/oven/furnace combination. The instructions are worn off of the unit and I have no idea how to light the furnace. The stove seems to work fine. The pilot light will not light and the fan won't come on. There is 12-volt power to the fan switch. Any help would be appreciated!
Nate, (Colorado Springs, CO)

Nate, try this; open the oven door and manually depress the spring-loaded button on the side of the oven opening, (I can't remember which side of the oven it’s on; you DO have an golden oldie!). This allows LP to freely flow to the pilot assembly. Be sure the LP container is opened and the pressure is correctly set to 11.0 inches of water column. The pilot flame should stay lit when you release the button. If it does, close the oven door. After setting the temperature on the thermostat, it will seemingly take an abnormally long time for the main flame to ignite. If you open the oven door to check, however, the flame will not light. A hidden lever encased in the side of the oven unit pushes the LP safety valve only when the door is closed. The fan should engage sometime after the burner has produced enough heat to be delivered through the vents at the bottom of the oven.

Unwanted Hot Water

I had to replace all the fresh water piping in my 1982 Coachmen RV. I replaced the cold lines and then the hot lines so that there were no mistakes. But when I turn on the cold water in the bathroom I get hot water for a short time, then it gets cold. What's up?
Peter, (Nesquehoning, PA)

Peter, due to the layout of some floor plans, it's not uncommon for a cold branch of the fresh water system to be physically connected very close to the cold inlet on the water heater. And without a definitive method of keeping the heated water from backing into the system tubing, it's inevitable that some of the water in the cold line at the inlet will also be heated. During the time your coach was manufactured, it was rare to find a backflow preventer at the water heater, such as common today. If you are sure you have indeed replaced the tubing properly, try this; Install a one-way check valve (backflow preventer), directly to the back of the water heater at the cold, input line. Keep in mind the direction of flow. It should be positioned so that water will flow into the water heater but not out. My guess is that some of the heated water at that inlet area is being siphoned out of the water heater and delivered to that one faucet when it's opened.

To test this theory, fire up the water heater and open the kitchen hot faucet making sure hot water is indeed flowing. Then turn that hot faucet off and open the cold water at the questionable faucet. Chances are the problem disappeared. Why? Because as the hot water was running in the kitchen, cold water was automatically entering the heater eliminating that small portion of heated water near the cold inlet and that branch leading to the bathroom. Installing the backflow preventer should eliminate this condition by prohibiting any heated water inside the tank from migrating back into the cold line those few, crucial inches.

Evacuation Vacuum

Dear Readers, in response to a query in an earlier column, I received a couple of emails regarding the use of a vacuum truck operating at a low vacuum to evacuate the holding tanks on the RV. There was caution alerted to the fact that if too much vacuum is exerted, that which exceeds the flow of air into the tank via the tank vents, the tank could then collapse. This is true. However, it was assumed the operator of the truck, (the writer of the original question), would understand the emphasis of using a very low vacuum for the evacuation.

All that said, the old Doc would like to add this addendum to the original request for the correct procedures. In addition to verifying the tank vents are indeed clear of obstructions, I would also recommend that the toilet flushing mechanism be held open to aid in the venting process of the solid waste holding tank. In the past I have an ABS tee fitting to keep the toilet flush valve open and still allow air to enter the tank at the same time. Also be aware that it will more than likely be necessary to add water to each of the “P” traps in the gray waste system after evacuation. Many thanks to those alert readers who voiced their concern.

(Note: To read the original question, go here.) 

Jack with Dinghy

Can I safely lower the jacks on my motorhome with my car attached to the hitch without damaging the jacks or anything else? Many gas stations are not level and I find that I need to level my coach in order to take on the most fuel. And, if I'm dumping, in order to drain the holding tanks fully, the coach should be level. It would be a real pain to have to disconnect the car every time.
Chuck, (Holland, OH)

Chuck, it should not pose a problem to activate the leveling jacks with the car attached as long as the tow bar, receiver hitch and ball mount have been properly installed. Unless you have quite a drastic angle to the "A" frame portion, the coupler will simply swivel very slightly on the ball as the coach finds its level position. Again, be sure the gas station and/or dump station is "relatively" level to begin with. 

I would avoid the practice if you are situated on significantly uneven pavement to start. Monitor the coupler/hitch area carefully as you attempt this the first time. There should be no contact between the rim of the coupler over the ball with any portion of the ball mount on the coach. If it looks as if the parts will make contact, stop the leveling process and unhook the car. And I agree, the RV lifestyle should not cause pain, but relieve it!

Thermoplastic Welding

I don’t have much experience with an RV, but I do have a polypropylene gas tank on my Dodge Ram 4x4 and it has a leak in the bottom. Do you have any suggestions on repairing this without removal of tank? I have tried some of the fiberglass repair kits but they did not hold.
Frank, (Savannah, GA)

Frank, the good news is that polypropylene, being a thermoplastic, can be successfully welded. Other thermoplastic tanks common to RVs are made from polyethylene and ABS; all of which can be safely welded. Cement-type repair kits, as you’ve found out, simply will not repair a plastic tank permanently; welding is the only viable method of a permanent repair in my opinion. Another plus, plastic welding can be performed safely on polypropylene gasoline tanks since the practice employs hot air or nitrogen rather than arcing and sparking. Simply draining the tank is all that is necessary. Remember though, the area must be clean and dry to effectively weld. The downside is that it takes specialty equipment in order to weld plastics. Check with your local RV repair facilities. Many shops have plastic welding machines since the same technology is used for polyethylene water tanks and ABS holding tanks as mentioned above. Some RV repair shops will indeed have a welder. Finding them is the difficult task. Let your fingers do the walking first.

By the way, if you'd like to learn how to do this yourself, drop me another email. I have a videotape that teaches pro technicians how to weld plastics.

(Note: For a similar question, that bounces back to the response above, check out this post from another reader)