New purchase 5th Wheel heater.

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Bochim

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Feb 9, 2014
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I recently purchased a Northwood 2011 Fox Mountain 245 rks. Really like the unit. When I turn on the heater it fires up and heats well. After temps rise and the unit shuts off it does not come back on. I can turn heater off and then back on and it will fire up again and then not come on. I suspect the thermostat but I’m not at all sure. Any suggestions? Thank you very much. Getting cold in Montana.
 

Matt_C

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Bochim,
It is very likely the contact in the thermostat are fouled. Pop the cover off and look for the two parts that touch to start the heater. Buff them just a little with an emery board or fine sandpaper. Then try again.
Matt
 

Kirk

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suspect the thermostat but I’m not at all sure. Any suggestions?
It is possible that it is the thermostat but in my experience that is one of the less common probabilities. It would help to know the make and model of the furnace and also of the thermostat. Do you have 1 thermostat that is shared by the furnace and the air conditioner? Keep in mind that the thermostat contacts are used every time and are seldom patterened if failing intermittantly.

To just guess without knowing more but based on many years of working on RV furnaces, the most likely cause of the problem is the ignitor probe. What often happens is that a small crack will develop in the ceramic that surrounds the high voltage probe and when cold it works but once it has been on that crack remains open just enough to supply a small path of carbon from the burning propan that shorts the voltage to ground when the furnace tires to light again. When that happens the furnace will try 3 times and then go into lockout. When you turn it off and back on it has had time to cool again and once more will work fine until the furnace is back to temperature but fail to relight again, over and over.
1663617112517.png
The picture is of one of the versions of probe from Suburban but other brands are very similar and all of them work the same way and are subject to that same problem. Your furnace is now 11 years old so if that is the original probe and has been used very much, it has done quite well.
 

Bochim

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Kirk, Thank you so much for your reply. I just got home and it is late. Will look at the make and model and get back with you tomorrow.
Thanks again, Steve
 

Bochim

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Matt,
Will try that tomorrow, thanks for the help. Probably needs to be done even if that is not the primary problem. Steve
 

Bochim

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Kirk, Thank you so much for your reply. I just got home and it is late. Will look at the make and model and get back with you tomorrow.
Thanks again, Steve
Atwood
Model#: 8531-LV DCLP
30,000 BTU
When I opened up the outside cover this afternoon the unit came on. My wife is working in the rv so I went and asked her if she turned it off and on, she said no. It cycled for the rest of this afternoon but seemed to be cycling fast. It would only come on for a couple minutes and then stop, only to come on again in a few minutes then repeat. Sorry I did not get the model number earlier. Steve
 

Bochim

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Atwood
Model#: 8531-LV DCLP
30,000 BTU
When I opened up the outside cover this afternoon the unit came on. My wife is working in the rv so I went and asked her if she turned it off and on, she said no. It cycled for the rest of this afternoon but seemed to be cycling fast. It would only come on for a couple minutes and then stop, only to come on again in a few minutes then repeat. Sorry I did not get the model number earlier. Steve
 

Bochim

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Totally botched up the replies and quotes. One is for Matt and the that is posted is for Kirk. Sorry for the confusion.
 

Kirk

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It cycled for the rest of this afternoon but seemed to be cycling fast. It would only come on for a couple minutes and then stop, only to come on again in a few minutes then repeat.
First, to troubleshoot you really need to get a copy of the Atwood service manual from this link.

Constant short cycling is often caused by the over temperature limiter that is shown in the center of this schematic from the service manual, page 8.
1663771123611.png
That may not be the case now as it doesn't sound like it fits with your original symptoms. The heat sensing for the ignition probe would not cause that type of issue but some type of bad electrical connection might. Have you tried removing and reseating all of the electrical connections that you can access?
 

Ex-Calif

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If your thermostat is a two wire mechanical unit as depicted in Kirk's schematic I'd recommend replacing with a digital one. Super easy to do. The advantage is better heat control and a digital temperature reading for cabin temp.

Also if you are parked up and planning to heat the RV with propane, get your wallet out. I did that for a few months in a mild Florida winter and was using 90 gallons(?) of propane a month. I ended up buying an el-cheapo electric one from WM with variable temp and 3 blower settings. One unit could easily burn me out of my 30 footer.

Especially nice as the park I was in did not meter electricity.
 

Old_Crow

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If your thermostat is a two wire mechanical unit as depicted in Kirk's schematic I'd recommend replacing with a digital one. Super easy to do. The advantage is better heat control and a digital temperature reading for cabin temp.

Also if you are parked up and planning to heat the RV with propane, get your wallet out. I did that for a few months in a mild Florida winter and was using 90 gallons(?) of propane a month. I ended up buying an el-cheapo electric one from WM with variable temp and 3 blower settings. One unit could easily burn me out of my 30 footer.

Especially nice as the park I was in did not meter electricity.
Gallons or pounds? I was on Mt Laguna, near San Diego last winter and even the week it dumped 18" of snow I only used a bit over 7 gallons. (30lbs). I was averaging one 30lb bottle a week through the winter.
 

Kirk

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If your thermostat is a two wire mechanical unit as depicted in Kirk's schematic
The thermostat also may be one that is shareed with the air conditioner. If that is the case, the 2 wires in the schematic that attach to the thermostat they show go instead to a circuit board in the air conditioner and that circuit board gets signals from the thermostat and then either uses them to control air conditioning of if the furnace is selected it sends the signal to the furnace, but to the furnace, if those two wires are connected together it means a call for heat and when they open it turns the furnace back of. Very simple electrically for the furnace.
 

Ex-Calif

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If your thermostat is a two wire mechanical unit as depicted in Kirk's schematic I'd recommend replacing with a digital one. Super easy to do. The advantage is better heat control and a digital temperature reading for cabin temp.

Also if you are parked up and planning to heat the RV with propane, get your wallet out. I did that for a few months in a mild Florida winter and was using 90 gallons(?) of propane a month. I ended up buying an el-cheapo electric one from WM with variable temp and 3 blower settings. One unit could easily burn me out of my 30 footer.

Especially nice as the park I was in did not meter electricity.

Yeah - I looked it up. 20 gallons or about 90lbs. I was using a tank a month which sorta jives with your 30lb a week. With propane at around $4 a gallon it was like $80 a month for propane for those few months.
 

Old_Crow

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Yeah - I looked it up. 20 gallons or about 90lbs. I was using a tank a month which sorta jives with your 30lb a week. With propane at around $4 a gallon it was like $80 a month for propane for those few months.
Yeah, but since I was "working" the company paid for mine, so I really didn't worry about it. Just took the empty tank with me when I took the bank deposit to town each week.
Up here in Bishop, I'm hooked to a 100lb tank. I'm on my second tank since April, however, as fall approaches my usage is going to go up.
When I travel, I carry 4 30lb bottles with me. Anytime I park for more than a couple of days, I hook up to the external tanks. I usually only have to fill the onboard tank about twice a year.
 
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