Faulty RV Oven

We really enjoyed your seminars at the FMCA Convention -- very informative! The gas oven in our motorhome just quit working. We have an Amana range/oven in a Winnebago. The burners on the range still work great, and I can light the pilot light in the oven. However, when I turn up the temperature control knob to set the oven temperature, nothing happens. The pilot light remains on but it seems that no larger volume of gas comes into the burner. Any ideas of what we might check? Thanks in advance! Linda N.

Linda, usually when the thermostat calls for heat, a signal is sent to a component called the oven safety valve. The safety valve allows the gas to flow to the oven burner. The signal however, is triggered by the thermostat. If the pilot flame does not get larger when the thermostat calls for heat, the faulty component is usually the thermostat. If the pilot flame indeed get larger and the main oven burner still fails to ignite, the faulty component is usually the safety valve. If you send me the complete Amana model number I can look up more specific information for you, but right now, I’d have that oven thermostat checked by a certified RV technician, as well as the delivery line gas pressure. The appliances must be fed the correct amount of propane at the correct pressure and that is determined by the pressure regulator down at the propane container. Of course, physical damage such as a kinked tube can also restrict fuel flow and negate burner ignition, but I’m assuming there is no kinked tubing anywhere in the oven system. Time to call the professional!

##RVT789 

Propane Leak in Range

I have a gas leak in a stove/oven around one of the compression fittings. I have done everything I can think of to fix it. Can I use some high-temp silicone around the tubing on the outside to fix it? Bob E. (WA)

Bob, you do not want to use silicone; it will not eliminate a propane leak. In fact, no sealants are permitted at all on propane gas flare fittings or compression fittings. Sealants are only applied to the male threads of pipe fittings, and most certainly, not silicone. If the compression ring inside the fitting is tightened too tightly, it's possible to lose the integrity of that fitting. I'm suspecting that's what happened in your instance. Or perhaps the threads on either portion of the fitting are stripped. In all cases of leaking gas fittings, it is recommended to simply replace the fitting in question. And be sure to perform (or have performed), a full coach timed pressure drop test to ensure there are no additional gas leaks in the coach. Do not use the appliance until the complete RV is deemed leak-free.

##rvt759

RV Oven Operation

The Suburban oven in our older RV is acting up. The pilot lights normally and when turning the control to a cooking temperature the flame goes large and the signal to light the burner seems to be received and the main burner comes on. So far so good, it appears to be working. The problem is the oven only heats to a certain point (not even 300-degrees according to a thermometer) and the main burner goes out, acting as if it reached the temperature the control was set at. It seemed to me a problem with the safety valve/control unit or the sensor, so I started looking around for a replacement part. A few dealers tell me there is no replacement part made and I have to buy a whole new range/oven control unit. Visiting Suburban's website does not shed much light except that if there was an "A" after the model number it would be a mercury free unit. I wonder if it could be retrofitted? Gord S., Edmonton, AB

At first read, Gord, the safety valve appears to be functioning normally, assuming the delivery line pressure is set correctly. Any pro RV service facility can quickly and easily set the propane pressure for you. With correct pressure, here's what happens when you set the thermostat to any cooking temperature: When the thermostat is set to a temperature (assuming the oven pilot flame is lit), the pilot becomes slightly larger and begins to heat the thermal bulb (or a thermocouple in a non-mercury valve) attached to the safety valve. Yours appears to be doing this now. This thermal bulb, when heated by the pilot flame, expands a bellows in the safety valve and allows the propane to flow through the valve and on to the main burner where it is ignited by the extended pilot flame. This results in a time delay from when the oven thermostat is first set to a desired temperature until the main burner actually ignites. Now all that said, it is a possibility you have a faulty thermostat (main oven control valve). But first be sure the temperature sensor inside the oven is clean and free from cooking oils, oven cleaner and grease, etc., before condemning the thermostat control.

Your problem may simply be a fouled temperature sensing probe in the oven. A coated probe can send incorrect info to the oven thermostat control. If faulty, however, the thermostat and temperature sensor must indeed be replaced as a single unit since an integral capillary tube connects them. Your first task should be to clean the temperature sensor in the upper reaches of the oven. But it's also possible the oven safety valve may be the culprit. The flame sense probe (thermal probe) at the oven pilot is an integral component of the safety valve and must be replaced as a single unit like the thermostat and its temperature sense probe. I'm sure this sounds a little confusing, but a certified RV service tech should be able to quickly diagnose the problem with a few measurements and a couple of operational tests. So, clean the temperature sense probe and have the LP pressure verified keeping in mind further diagnosis may still be required. I don't believe it’s plausible, or even possible to replace a mercury safety valve with a non-mercury valve without drastically modifying the range. And it certainly is out of the realm of the do-it-yourselfer. 

##RVT803; ##RVT897

RV Oven Flashback

My propane RV oven experiences regular flashbacks to the air shutter at the back of the oven. I have tried adjusting the shutters to no avail. Any suggestions on how to fix this?
Waldo, (Palm Springs, CA) 

Waldo, the first thing to check (or have verified) with any propane appliance issue is the delivery line pressure. Too low or too high LP pressure can cause a plethora of operational issues with any and all of the four propane-burning appliances. It’s quite possible the delivery pressure is set too high. Setting the pressure to the correct level necessitates the use of a manometer which any certified RV service tech will have. 

Once the LP pressure has been set to 11.0 inches of water column, the next item to check would be the cleanliness of the main oven burner. Most can be removed with relative ease. Inspect each of the holes in the burner. Look for plugged ports, soiling by cooking greases or possibly an accumulation of oven cleaner or other debris blocking some of the ports.

Next, though in the oven it’s rarely adjustable, check that the oven burner assembly is in alignment with the orifice fitting at the safety valve near the back of the oven. Any misalignment may cause turbulence inside the mixing tube, much akin to a related problem associated with the water heater. The incoming propane draws in air from inside the oven to be mixed prior to it being consumed by the burner. 

Another item to check is the orifice fitting itself. It can be removed, soaked in acetone or a like liquid and then allowed to air dry. Much like the ports in the burner, it is possible cooking oils may have partially blocked the oven orifice. 

Finally, the air shutter should be adjusted so that the main burner flame is steady, with sharp blue points and not lazy or “floating” above the ports. One other cause of your symptom may be a damaged or bent burner assembly. But a close inspection will reveal if that’s the case.

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.

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.

LP at the Range

I have an early 90s Atwood/Wedgewood range/oven that will not fire up. It appears to have no gas going to it since I have turned the burners and oven on and never smell gas. There is no air blowing through the line because the match never blows out either. I looked for a hidden gas valve, but none was found. Is this a regulator problem or is something plugged up? I just bought this RV and maybe it NEVER worked?
Julie, (Boise, ID)

Julie, indeed something is amiss and I kinda hate to ask this....but are you sure there is fuel in the container? Also, are you aware if the RV is equipped with an LP leak detector that employs an automatic shut-off solenoid valve? The solenoid valve will be positioned at or near the service valve at the LP container. If you have fuel and you see no shut off valve near the container or under the stove top, then the LP line must be kinked or disconnected somewhere further back in the delivery system; if indeed LP is flowing at all. 

Try this; be sure the LP container valve is open and light another appliance such as the refrigerator. If you cannot light any appliance, then I would suspect either the container valve is stuck closed or the main LP regulator positioned at the container is faulty. But if the refrigerator ignites and remains lit for say, thirty minutes, one can safely assume that LP is at least getting into the system. Distinguish the flame at the refrigerator before proceeding to the next step. 

Next, at the stove, saturate the flare nut fitting where the gas line attaches to the manifold with a soapy solution, (be sure to avoid soaps or detergents that contain ammonia products). Then, using two wrenches, slightly loosen the flare nut. If no bubbles materialize as this fitting is loosened, there is no fuel getting to the range. Your only recourse is to follow the copper tubing from the stove down to where it “tees” into the black iron piping. It's not improbable that that section of tubing is kinked somewhere or that it has been disconnected altogether. 

Be sure to inspect every turn and twist as the tubing is routed behind cabinets and through the flooring. There is the remote possibility of a blockage in the black iron piping, but I would suspect that, at the very worst, you may have to run a new length of tubing from the black iron connection up to the range manifold. If all tubing and piping is in good shape, the blockage may be in the stove top manifold itself and further troubleshooting there is in order.

Oven Flame Question

I’m having a problem with my range in my RV. The oven has probably never been used. When you turn it on, the pilot lights immediately. The problem is the flame on the main burner stays at full fire. Whether you set it for 200-degrees or 500-degrees there is no change in the burner flame. It is not adjusting. Is this something stupid that we can fix or do we need a professional?
Peter, (Rockland, MA)

Peter, what you've described actually sounds normal. The main burner flame will be the same size regardless of what temperature you set the thermostat to. The burner flame remains constant until the set temperature is finally reached, then it simply shuts down, leaving only the standing pilot flame lit. But the flame will look identical no matter what setting you choose. It just goes off faster at the lower temp.

Now if the main burner flame remains on well past the set temperature, then the thermostat could indeed be faulty. If this is the case, before condemning the thermostat, clean the flame sense probe located in the upper rear portion of the oven, (see photo). It is usually suspended in clips of sorts. It should not be touching the oven sides. If the flame sense probe has a layer of oven cleaner or cooking oils, etc., it will not properly sense the temperature accurately. If, after cleaning the sense probe, the oven still will not shut off when the temperature has been reached, it will be necessary to replace the complete thermostat.

No Oven Operation

My Wedgewood oven will not light the main oven burner. The pilot light will light, but when the thermostat calls for heat the main gas valve will not open. I'm just not sure if the pilot flame increases in size or if my pilot flame is just not big enough to heat the thermocouple. It seems very small, but if I wiggle the thermostat, it will briefly get bigger. The way it burns on just the pilot position is definitely not big enough to reach the burner. I have checked the LP pressure and checked the pilot orifice for blockage. These items are good. Any help would be appreciated.
Norm (Kelowna, BC)

Norm, typically after the thermostat calls for heat, here is what happens; assuming the pilot flame is already lit in the oven, when the thermostat is set to any temperature setting the oven pilot should become slightly larger or elongated, (this is also called the extended pilot or high fire), and begins to heat the thermal bulb (it’s not a thermocouple) attached to the safety valve. This thermal bulb, (see photo), when heated by the extended pilot flame, expands a bellows and opens a pathway in the safety valve and allows the LP to flow from the oven thermostat through the safety valve and on to the main burner where it is ignited by the pilot flame. That is why there is a time delay when the oven thermostat is first set to a desired temperature until the main burner actually ignites. Now if there are any blockages in the pilot orifice or its assembly, or if the flame deflection shield is mispositioned, the extended pilot may not fully engulf the thermal bulb of the safety valve. I’d suggest disassembling and cleaning the pilot assembly once again (some spider nests are quite stubborn!) and making sure the thermal bulb is held securely by the small locking screw or against the stop tab. Then run the test as explained below, keeping a close eye on the pilot size. It may be necessary to temporarily remove the main burner flame spreader in order to get a clear view of the pilot assembly. While watching the pilot flame, turn the oven thermostat knob up above 300-degrees F. Immediately, the standing pilot should expand and envelope the thermal bulb portion of the safety valve. If it fails to gain in size, the thermostat is faulty. If it indeed becomes bigger and engulfs the thermal bulb yet the oven main burner fails to ignite, then the safety valve is faulty and needs replacing. The positioning of the thermal bulb in the extended pilot flame mandates it must be fully in the fire of the extended pilot in order to heat the mercury inside.

Also, in some ovens, there is an oven pilot adjustment on the face of the thermostat. If the standing pilot is too small to begin with, the extended pilot might not reach the thermal bulb when the thermostat calls for heat. Remove the thermostat knob and see if there are any adjustment screws visible through the fascia of the front stove panel. You’ll want the standing pilot flame to be large enough to protrude slightly above the height of the pilot tube, but not too large that it heats the thermal bulb in the “OFF” position. If the LP pressure is at 11-inches water column coming into the range and the pilot orifice is clean and adjusted properly, the thermostat and safety valve should work together to get that main burner lit. The good thing is that by running the above tests, you can pinpoint the faulty component before having to tear the range apart.

Size Does Matter

I have an older RV I am trying to fix up. I would like to know if it is advisable to use 3/8-inch copper tubing for my stove/oven instead of 1/2-inch. It would only be about 3-feet long coming from the elbow that has a 1/2-inch line going to the LP container about ten feet away. Lastly, should I use all flared fittings instead of compression fittings on propane lines regardless of size? Any help is appreciated.
Carl, (Ft. Worth, TX)

Carl, many motorhomes today come equipped with 1/2-inch copper tubing for the branch runs of the LP distribution system though you’ll still see some units outfitted with the smaller 3/8-inch copper lines. LP gas piping systems are sized by the BTU demand load of that particular RV. Of course, you’ll also find black iron piping used for the main manifold with the copper branches going to each appliance. Unless your range is a “high demand” appliance, you should be okay with a short run of 3/8-inch tubing. But only use SAE pipe fittings and flare fittings; and use no sealant of any type on flare fittings. Compression fittings are not allowed in the LP delivery system even though you may find some utilized inside LP appliances.

Burner Burdens

I have a three-burner propane stove in my RV that seems to take longer and longer to perk a pot of coffee. I recently took a trip in a friend's RV and noticed his propane stove perked coffee much faster. On inspection I noticed the flames on his burner were about 1-inch tall and were a nice two-tone blue. On my stove while the flames are blue they are only about 1/2-inch long. Is there something wrong with my burners? My incoming line? The tanks show a constant 150 pounds pressure with no leaks. Are there newer burners that burn hotter?
Dan, (Lacey, WA)

Dan, indeed the design of the burner head itself has a lot to do with the structure of the flame emitting from each port, but the BTU rating of each burner is determined by the orifice size at the burner valve itself. The larger the orifice, the more LP is allowed to pass through and into the mixing tube. In today’s RV stove top, the mixing of air with the incoming LP is usually non-adjustable, so the only variance in the equation would be the delivery pressure of the LP. It is important to have the delivery line pressure checked annually at the very least. It should measure 11.0-inches of water column which is a very small amount of pressure. 11.0-inches equal four-tenths of one pound per square inch, (.4 PSI)! I’m guessing your LP pressure is lower than normal. That, coupled perhaps with an obstruction at the burner head itself, will result in a much smaller visible flame at the burner head. It’s time to have the pressure adjusted or at least checked. Because the LP pressure is relatively slight, it can only be adjusted while monitoring and measuring with a manometer. Never attempt to adjust the pressure without using a manometer. Unless you’ve had specific training in the use of a manometer, I would suggest you make an appointment at your local RV service facility. It’s a quick and easy job to measure and adjust the LP pressure and at the same time, check the entire coach for LP leaks.

Growling Oven

I have an Atwood RV range. It is a Wedgwood model. The thing that I am curious about is that the oven sometimes makes a growling sound rather than the smooth hissing sound that an oven usually makes. It seems to operate normally otherwise. Can you tell me what is causing this or if something needs to be replaced?
Jim, (New Bern, NC)

Jim, the growling noise you are hearing is probably caused by a fuel delivery or air mixture problem. Since proper combustion requires mixing LP with air, the oven compartment is vented through the cooktop to allow air to enter the oven as well as cooking odors to be exhausted. Therefore, please make sure there is no aluminum foil lining the burner box directly under the cooktop. Although this does tend to keep the stovetop burner cavity clean, it can easily affect the secondary air mixture in a negative way. Likewise, be sure nothing blocks the horizontal opening in the upper rear section of the oven compartment. Using a flashlight, perform a quick inspection of the primary air inlet at the rear of the oven burner tube. You may also have to remove the bottom oven pan to actually see it. This air shutter controls the amount of primary air that gets mixed with the LP on its way to the burner. Make sure the air shutter opening is not obstructed. You can clean it with low pressure compressed air or a clean rag. If there is no visible air restriction, you should have the LP system inspected and the delivery pressure measured by a qualified RV service technician. A manometer must be used to measure the LP pressure and only a qualified tech should adjust the air mixture to ensure a proper flame and for optimal combustion.