Obsolete RV Furnace

I have a SOL/Aire furnace as far as I can tell. The unit runs and heats fairly well. The problem is when it starts up the first time and for a while after. It starts good but backfires on startup. The blower comes on and then it will start to pop. Gas pressure is correct and all other equipment runs good. Someone suggested I check for cracks in fire box?
Dick, (Schenectady, NY)

Dick, as far as I can remember, replacement parts for Sol-Aire furnaces are no longer being produced, including the firebox/combustion chamber. Unfortunately, the Sol-Aire had a propensity for the burner to literally burn away during those popping instances. According to some, it had something to do with the design of the burner. And over time, those mini-explosions would eventually blow a hole right in the burner mesh. You may be able to find some repair centers still with replacement parts, but it would simply be hit and miss I’m afraid. The best bet is to begin searching for a replacement furnace that will fit in that same location. I wish I had better news, but obsolescence is something that just happens within the world of RVs from time to time.

Rippling RV Refer

While running the refrigerator on LP it will light and run but only for a short while. I did the normal cleaning of the burner, the burner jet, the ignitor. I did a test for dirty power at the DC terminal block even though it’s on the LP mode. On the AC scale I read about 6-volts or less at the connection. Is this correct? Could my converter be faulty? I tested it while plugged into shore power. I have a 45-amp power converter with a charge wizard.
Joe, (McKeesport, PA)

 
Joe, though you didn’t specify the brand of refrigerator in your motorhome, I believe you have a Norcold. Excessive AC ripple can indeed cause the problem. In order to verify that this is the case, make sure the house batteries are fully charged and in good condition and then disconnect the AC shore power to the coach. This will remove the AC source and therefore the ripple. The refrigerator should function normally on the propane mode and powered by the batteries. If you continue to have this problem with the camper running strictly on 12-volts only, the problem lies elsewhere. In this case you should suspect faulty or loose connections, faulty or intermittent gas valve, flame sensor, low propane gas pressure or a faulty control board. 

I’ll assume the LP container has fuel. If the unit operates properly, then we can assume the problem is indeed AC ripple. The first check is to make sure the refrigerator is connected to the filtered side of the converter output. If it is connected to an unfiltered output, excessive ripple is likely to occur. On the fuse panel, some of the circuits will be filtered and some will be unfiltered, these should be indicated on the panel labeling. Identify the wiring for the refrigerator and ensure that it is connected to a filtered output circuit. If not, swap it with a “non-critical” circuit and run the operating test once again. If the refrigerator is connected to a filtered circuit, there could be a problem with the filter in the converter and further troubleshooting of that device should proceed.

Replacing RV Carpeting

I have an older (1987) motorhome and would like to replace the worn carpet. How is this carpet originally installed by the factory? How do I install the new carpet? I’m very handy, but I need to know the correct procedures.
Paul, (Worthington, OH)

Chances are, Paul, the original carpet was simply stapled to an underlayment of plywood or pressboard. Keep in mind that during manufacture, some RV floors are fully carpeted before the partition walls, cabinets and furnishings are installed so it’s doubtful you’ll be able to remove every square inch.

Complete removal is not always necessary, however, since the old carpet itself can be selectively retained in closets and under storage cabinets. If the existing carpet was installed before the cabinets and partition walls, carefully cut along the walls and cabinets with a sharp razor knife to cut out the old carpet. Save these pieces. They may be used as a pattern for the new carpet. Be sure to check the floor area carefully after removing the old carpet.

Completely sweep the wood flooring clean and sand any rough areas. Cabinet doors that are low to the floor should also be removed for easier handling of the new carpet. If a thicker carpet and pad are going to be installed, some cabinet doors may have to be repositioned to accommodate the added thickness of the carpeting. In most cases, this is not a major concern, but I do recommend a thick carpet pad. Get a good one.

As mentioned, any removed sections of the old carpet can be used as a pattern for cutting the new one but it is wise to leave a little extra material all the way around the perimeter and trim the pieces to fit exactly at the time of placement. A razor knife with a new blade works best for cutting virtually all carpet materials. Stock up on blades and change them often during the installation process. Use a metal straight edge whenever possible to produce a nice, crisp edge.

After cutting the carpet to fit, lay it out flat inside the coach and work from one end of the motorhome to the other. Force the new carpet into the edges at the cabinets and carefully trim the remainder of the excess with a sharp razor knife. Since the area in the RV is relatively small, a carpet knee-kicker is usually not needed; just a decent staple gun. There are other means, but the stapler reigns supreme because it is fast and easy to use and the staples are easily concealed within the pile of the carpet. It is recommended that an electric or air-powered stapler be rented or otherwise obtained for the task of securing the carpeting.

Double-faced carpet tape is also quite handy for attaching the carpet in close quarters or under cabinets where a stapler may not fit. In most motorhomes, there is a point where the carpet meets linoleum, tile or a wooden section of the flooring. One transitional method is to simply fold the carpet under and staple it to the floor. When folding the carpet under, remove the woven backing from the carpeting first, then cut the pad back the width of the fold (about 2-inches or so), so that the folded carpet lays as flat as possible.

There may be another preferred method for that style of carpeting such as a metal or wooden threshold molding. After the carpet has been stapled to the underlayment, remount any furnace ducts or cabinet doors that may have been removed prior to the installation. Keep in mind; it may be necessary to raise some cabinet doors to provide enough clearance above the carpet for the door to swing freely.

When carpeting in the lavatory, it is best to remove the toilet completely and to allow the carpet to cover the floor all the way up to the perimeter of the floor flange. After installing the carpet, reinstall the toilet. Taking your time, double checking measurements and using a sharp razor knife will make the job of carpet replacement a fairly easy task. Additionally, a new carpet will reflect a personal touch that can be enjoyed for many, many miles. And it always adds to the trade-in value.

Complete RV roof replacement is a job for the pros

My RV roof leaks in several places and the roof sagged around the air conditioner. While surveying the damage I determined that the roof is constructed in layers including rubber material, plywood and foam. The air conditioner mounts to a 2' x 6' piece of plywood that is supported only on one end; like a diving board. I think I need to replace all but the foam and some of the rafters. Can you offer advice on the best way to proceed for a do-it-yourselfer?
Roy, (Harrisburg, PA)

Roy, extensive damage from water leaks usually mandates a complete roof replacement; a major repair best left to the professionals. Here's a typical process when performed in the shop.

First, every component from the entire roof area, A/C, all vents, antenna, running lights, storage pods, racks, ladders, etc., must be removed. All the side trim, awning rail, drip molding, etc., will also have to be carefully removed.

Typically the rubber membrane is cemented to the plywood substrate and folded over the sides of the RV and stapled prior to the trim pieces being attached. At the front and back there may be a flat molding strip or the membrane might simply tuck under a fiberglass cap. All of the rubber membrane must be removed and the damaged plywood sections located. In some cases, the water may have permeated the foam insulation and possibly the interior ceiling paneling. All damaged insulation and interior pieces will also be replaced when necessary.

All damaged or warped wood rafters will be replaced with new. The technicians should gradually taper the rafters to the ends so that they are thicker in the center. In other words, it create a slightly crowned roof. This will eliminate low areas and ensure proper water drainage, especially at that sunken air conditioner location.

Once all the new insulation and rafters are secured, the entire roof is covered with new plywood. In some cases I recommend 3/8-inch plywood, though 1/4-inch will usually suffice. Extra care is taken to make sure the seams between the panels are very tight. There should be no screws or staples sticking up above the level of the plywood. The seams must remain flush and smooth so the EPDM rubber will not tear or crease during installation. Additionally, the good installers bevel the edges of the plywood slightly at the sides of the roof. This whole preparation stage is crucial!

If the cement used is a bonding-type, such as contact cement, it must be applied to the bottom ply of the EPDM as well as the plywood substrate. When a water based adhesive or pressure sensitive cement is used, it is applied only to the plywood. The EPDM membrane should be long enough so it can be rolled out the entire length of the RV. It should also extend over the sides of the RV; enough to fold down behind the drip molding or awning rail. Typically, installers fold back the membrane front to rear about halfway and apply the cement by brush, roller or spray gun.

If a solvent-based contact cement is employed, it is applied to both the substrate and the membrane and allowed to dry. If they use a water-based, pressure sensitive adhesive, it is applied to the membrane while the cement is still wet. They then will roll out all air pockets from the centerline of the coach to the sides with a lightweight roller or a push-type broom. At the RV sides, the material is folded over the edge of the roof and stapled to the sidewall on top of the siding material.

Butyl tape or caulking is applied to the back of a drip channel or awning rail prior to reinstalling it to the sides of the RV. Excess material hanging below the molding or rail is simply trimmed off with a razor knife. After the roof is completely cemented in place and secured around the perimeter, all the openings for the sewer vents, the refrigerator vent, the 14-inch vents, the roof air conditioner opening etc., are cut with a sharp pair of scissors. They should always radius the corners to eliminate the possibility of the EPDM tearing. If possible, excess rubber is folded into the opening and stapled to the sides of the opening. Butyl tape is applied and the vents are installed as usual and all screws, flanges and edges are sealed with Eternabond tape.

The pro shops will then leak test the entire roof to be sure there is no possibility of water intrusion. (See why this is typically not a D-I-Y job?) Let the pros handle a complete roof replacement.

RV Batteries and a Cold Winter

What is the best thing for RV batteries during the winter? I have a new motorhome and this will be its first winter. Should I leave the batteries in and keep the coach plugged in or should I take them out and store them for the winter? How about the engine battery? Some people take them out, some people leave them in. Which is best? If I take them out should they be charged once in a while?
Gary, (Ludlow, KY)

Gary, it is always recommended to completely remove all the batteries during a really harsh winter. Fully charge them before storing them in a clean, dry location in a warmer shed or garage. A fully charged battery will freeze only if the temperature dips to 55 or 60-degrees below zero, while a discharged battery may freeze at or near 20-degrees above zero. But it’s still best to remove them from the RV and avoid freezing temperatures when possible. There is probably no need to apply a charge during the actual storage period, but fully charge them just prior to re-installing them in the spring.

It is only advisable to leave the RV plugged in during the storage period if the coach is equipped with a computer-controlled, three-phase battery charger; one that monitors and adjusts the charging voltage and current accordingly. Otherwise, there is a great risk of overcharging the batteries and/or boiling out the electrolyte.

Triple Axle Electric Brake Problem

I have an F-350 pickup pulling a Newmar Mountainaire fifth-wheel. I have been using a Jordan brake controller. The RV has three axles with six brakes. Until recently the RV braking has worked flawlessly. Last week while applying the brakes the amperage readings on the Jordan display, jumped up to 30-plus amps. Normally the readings are between 9.5 to 12-amps. On one of the next brake applications the controller emitted a puff of smoke and quit functioning. Upon inspection I find that along with the blown brake controller, the Ford under-hood fuse box, which controls the trailer charging circuit was also blown. Can you shed any light on this problem? I cannot find any apparent short circuit in either the truck or RV system. Could a shorted out brake magnet in one of the wheels cause these troubles? Could there be two different problems? --Rocky, (Livingston, TX)

Rocky, though it's possible you have two issues, I feel it’s unlikely. Normally, the larger brake magnets will draw almost 3-amps each under full load. Considering the safety ramifications, it would be prudent to remove each wheel assembly and inspect each magnet. It could be that two or more may be internally shorted. Each magnet can be bench tested if a doubt exists.

The fact that the Jordan measured no more than 12-amps leads me to believe that two of the magnets were not even in the system to begin with. Inspect as much of the brake circuit wiring on the trailer than you can eyeball and look for loose, worn or shorted connections. Check each connection behind the backing plates carefully. Where the brake wires enter each axle can also be an abrasion point. Also inspect the umbilical between the truck and trailer. If the cord was pinched at or near the hitch assembly during a hard right-hand turn for instance, both the charge line and the controller could become shorted. Check also that the controller is not wired through that charge line fuse. My educated guess is the problem lies within the brake circuit and/or charge line itself.