Atwood furnace problem

[supersuit]

We have a 2011 13RDB which we bought used in 2013.   On a recent trip to the Green Mtns in VT., I had trouble getting the furnace to light.  I tried it at home while on shore power and it fired right up, although I did have to jiggle the thermostat to get the furnace to come on.  That night in VT, at 34 degrees, I tried the furnace.  No go.  The next day I took the cover off the thermostat and found that the contact which is held off by the on/off switch, wasn't making good contact with it's circuit.  I was able to push it in by hand (finger) and the furnace blower started but furnace didn't light.  After a few tries it did light and ran well.  Later that night I tried all my tricks and the furnace would not light, time after time, although blower came on, but timed out.  Same thing on the next day and one following.  Upon arrival home, I plugged back in to shore power and tried furnace using my finger trick....It lit and ran fine.  I'll replace the thermostat, but why would it not light on battery 12 volts but light when hooked to shore power??--same 12 volts in my mind.  Any suggestions appreciated.  We have a new 12 volt deep cycle battery.  Thanks. 

[david]

Can't say why it would work on shore power and not at the campsite, other than the converter output voltage is about 13.5 whereas a fully charged battery not connected to shore power/converter is 12.6. That might make a difference if the connection was just marginal.

But the Attwood thermostat is pretty cheap. Let us know if you find something better.

David

[charliem]

[font size="3"]What was the elevation in the Green Mtns, VT and back home? The non-lighting burner may be an elevation (fuel/air mixture) problem. The thermostat should be replaced. Upgrade it to an inexpensive battery powered digital thermostat. Several of us have done that; great improvement.
[/font]

[daplumbr]

I want to replace the OEM thermostat. Does anyone have a specific recommendation for a battery powered digital replacement? 

[charliem]

[quote source="/post/4276/thread" author="@sandroad" timestamp="1413511573"]I want to replace the OEM thermostat. Does anyone have a specific recommendation for a battery powered digital replacement? [/quote][font size="3"]Follow my posts here: [a href="http://livinlite-owners.com/thread/12/new-thermostat-21rbshttp://"]http://livinlite-owners.com/thread/12/new-thermostat-21rbshttp://[/a][/font]

[supersuit]

Thanks for the tips.  The elevation from my home in the Adirondacks is just about the same as where we were in VT.  A Roadtrekker friend suggested that my popane pressure may be low, but that doesn't explain the shore power/battery discrepancy.  I'll let you know what I find out when I solve the problem.

[charliem]

[font size="3"]If it's not an elevation problem, and it works on shore power but not plain battery, it might be a battery connection problem. The furnace requires a good 12V supply for the spark igniter and the gas flow valve. If the 12V supply is marginal either may fail to function. The trailer wiring is such that a poor battery connection will degrade the battery supply, but not the 12V from shore power. This can happen even with a known good battery. Check the other 12V appliances, particularly the higher current devices such as fans or incandescent lights if you have them, with shore power disconnected.  A voltmeter can help isolate the problem.   
[/font]

[bgewin]

I'm having a similar issue.  Two factors that are probably contributing are temperature (below freezing) and elevation (7500 feet).  I can get it to light if I run the cooktop burners for a while.  I need to find a quick and reliable way to get my furnace to ignite.

[david]

Unless the propane hose and connections are perfect, the propane pressure will bleed down over time- a week or so and air will get in. Then when you open the tank valve and pressure the system up again, it will have a mixture of air and propane and will usually not light.

So, after turning the propane back on after sitting for a while, I light the stove. It often takes almost a minute to purge enough air out of the system for it to light. Then I try to start up the propane refrigerator. It usually takes three start, stop and restart cycles to get it to light. Take the vent cover off and feel the aluminum draft tube just behind the burner- it will get warm quickly. If it is quiet around, you can also hear the burner.

Then I start the water heater. After purging the stove and fridge, it starts right up first time. I have only tried the furnace a few times but after getting the first three to light, it has always lit for me.

David

[peislander]

[quote source="/post/17535/thread" timestamp="1452105198" author="@david"]Unless the propane hose and connections are perfect, the propane pressure will bleed down over time- a week or so and air will get in. Then when you open the tank valve and pressure the system up again, it will have a mixture of air and propane and will usually not light.

So, after turning the propane back on after sitting for a while, I light the stove. It often takes almost a minute to purge enough air out of the system for it to light. Then I try to start up the propane refrigerator. It usually takes three start, stop and restart cycles to get it to light. Take the vent cover off and feel the aluminum draft tube just behind the burner- it will get warm quickly. If it is quiet around, you can also hear the burner.

Then I start the water heater. After purging the stove and fridge, it starts right up first time. I have only tried the furnace a few times but after getting the first three to light, it has always lit for me.

David[/quote]My experience has been the same. It's that "minute to purge" that is stressful. I just keep clicking the stove starter over & over until it starts all the time thinking the small trailer might become a mighty bomb (with me inside)...

[billmoore]

For that initial purge, it is safer and easier to use a long handled lighter. Just light the lighter, put near the burner, turn the burner on, and keep the lighter going until the burner lights.

[scout]

Although not an electrical issue...I had a stuck spring on my side mount regulator at the tanks. I just backed it off a bit in the cold weather/altitude (2013 13 RDB) a red led flashed at the furnace when there is no propane supplied to the unit ...you can see it through the vent cover, or better yet take the cover off...hope this helps...

Also x 2 on what David says with the stove top and fridge purge...sometimes i'm at 5-6 attempts for the fridge to ignite, have not had an issue with the hot water heater though...

[peislander]

[quote source="/post/17543/thread" author="@billmoore" timestamp="1452121604"]For that initial purge, it is safer and easier to use a long handled lighter. Just light the lighter, put near the burner, turn the burner on, and keep the lighter going until the burner lights.[/quote]Great Tip! --- That has to be much more safe.  8-)

[supersuit]

Sorry, I haven't been on for quite a while.  I solved my sporadic furnace problem (won't start unless I juggle, push/pull on thermostat) by installing a Honeywell 2 wire thermostat with an off position.  I bought it at my local hardware store and the furnace has never failed to start again.  Also, I always do the same propane purge procedure outlined by David, above.  Lighting the stove first gets most of the air out of the system and gets the propane real close the the refridgerator on my 13RDB, helping me get the fridge going in 2-3 tries.  The furnace always starts on the first try, then, as I think it has about a 45 second time out which isn't reached.  Jim

[scout]

good to know, I think found my new project prior to heading out this weekend...thx Jim