Heat, I need heat

JBM3M · 10-21-2022, 06:09 AM

Hey folks. When we went to bed heater was working fine, get up and it will only cycle to the fan blowing before the light of the fire, and it runs a minute or so and shuts off. We have to turn off the heater at the thermostat to get it to cycle again. Due to location of heater I really cannot do alot to diagnose or fix it. IDEAS?

bsmith0404 · 10-21-2022, 06:37 AM

Mine did the exact same thing a few years ago. Cycling it worked for a couple months, then it just wouldn’t light. Had a bad control board.

jasin1 · 10-21-2022, 06:40 AM

if there is a flame sensor on it it could be dirty…after so many tries it locks out at the control board…turning tstat off and on may start the 3 tries over again.. high limit also could do that if you have some vents closed and it’s overheating …sailswitch i believe only tries once and then fan stays running but could be wrong on this

JBM3M · 10-21-2022, 06:47 AM

no blocked vents. Cannot hear the igniter work at all, but the fan is blowing. I wonder if killing all power and restarting will help?

bsmith0404 · 10-21-2022, 06:54 AM

If it’s not trying to ignite at all, that could be the sail switch. The sail switch tells the control board the blower is running. The control board will not try to ignite if it doesn’t think the blower is running. If it tries to ignite or if it invites and runs for a few mins and then shuts down, it’s probably the control board. Easiest way to hear if it’s trying to ignite is to go out by the exhaust port and listen. Sometimes it’s hard to hear inside the RV with the blower running, especially if you have a hearing loss from working around jets for several years lol.

**flybouy** · 10-21-2022, 07:01 AM

Quote:

Originally Posted by JBM3M

Hey folks. When we went to bed heater was working fine, get up and it will only cycle to the fan blowing before the light of the fire, and it runs a minute or so and shuts off. We have to turn off the heater at the thermostat to get it to cycle again. Due to location of heater I really cannot do alot to diagnose or fix it. IDEAS?

Are you plugged into shore power? Do you know the condition of your battery? Have you confirmed that there is suffiant LP gas, i.e. you light all stove top burners and the burn with a strong blue flame? Nothing blocking the furnace intake and exhaust vents outside? Those are the first simple things to check.

JBM3M · 10-21-2022, 07:06 AM

well from these responses, looks like no heat this trip, we do have the electric fireplace but circulation of the heat sucks.

JBM3M · 10-21-2022, 07:08 AM

Well during the night no shore power, gen running now and problem still exists, checked the propane, all is good. Nothing blocking anything, and like I mentioned it worked last night when we went to bed and during the night. But at some point it stopped.

JBM3M · 10-21-2022, 07:25 AM

Yep, cannot hear igniter at all. BUT did remember we had a space heater with fan that is sufficient for the balance of the trip, temps are only in 50's so not that cold.

Are these control boards standard across the board for Dometic or Attwood heaters? Can't remember which I had, and too lazy to remove that louvered cover.

**flybouy** · 10-21-2022, 07:33 AM

Quote:

Originally Posted by JBM3M

Well during the night no shore power, gen running now and problem still exists, checked the propane, all is good. Nothing blocking anything, and like I mentioned it worked last night when we went to bed and during the night. But at some point it stopped.

If your running on battery at night then the longer and more frequently it runs the more it deplets the battery. The fan will not run at the speed required to operate the sail switch. If this happens repeatedly the furnace can lock out. Remove shore power/ generator, remove battery cables and let it set for a min or two. That should reset the furnace.

What type battery and how old is the battery? Typically if the battery is the one provided by the dealer it's usually an RV/ marine dual purpose starting battery ( has a cold cranking rating) and they are not very good for boondocking.

JBM3M · 10-21-2022, 08:11 AM

Will try that later, we have to run over to meet someone for a couple hours. Batteries are what came with it, I assume factory (we bought used).

**flybouy** · 10-21-2022, 08:52 AM

Quote:

Originally Posted by JBM3M

Will try that later, we have to run over to meet someone for a couple hours. Batteries are what came with it, I assume factory (we bought used).

The factory does not install batteries in most campers. IIRC only select units that have certain solar panels and related equipment come with batteries from the factory. The majority are supplied by the dealer at time of delivery. If you're battery(s) are OEM then they likely aren't holding a full charge. They would be 5 yrs old and odds are have been discharged to the point of being damaged. Each time a flooded lead-acid battery is discharged much past 50% it will cause the battery to loose more of it's capacity with each event.

I would have the battery load tested before spending money on a furnace control board. If you boondock often then I suggest upgrading to two 6vdc golf cart batteries at a min.

bsmith0404 · 10-21-2022, 09:01 AM

As mentioned, try the reset, but if your plugged into shore power, even with bad/weak batteries, it should work. Of course, key word is should, if the batteries are bad, replace those first. Also, if it’s not trying to ignite at all, it could be the sail switch instead of the board. The switch has to tell the board that the blower is running, without that signal, the. Oars won’t try to ignite.

JBM3M · 10-21-2022, 12:14 PM

Okay, except it is raining (finally) so waiting for a pause to disconnect the batteries. The batteries are always on a charge unless we are away from the RV. At home it is always plugged in.

Not buying anything yet, got to get this figured out and we are at a gettogether so working on it would be too many chefs type situation. I will do the reset when the rain eases.

We have needed rain so bad here in Washington, I cannot complain. Even the smoke is finally gone from the forest fires.

**sourdough** · 10-21-2022, 12:28 PM

A note on those batteries; if they are the OE (you don't know and bought it used) and haven't been maintained they could be toast. If for some reason they are bad the will drain the output of your converter and affect the operation of the rest of the trailer as the damaged battery(s) suck up the output of the converter.

I had one that did something similar (been a few years ago) and I reset it by pulling the power lead on the control board inside the outside cover (Atwood) vs pulling the battery cable. Might be easier if that is possible on yours. IIRC that problem turned out to be the control board.

jsb5717 · 10-21-2022, 12:35 PM

If the batteries are not drained and the fan is running then the first thing to check is the Sail Switch. Access may be difficult but that's the likeliest culprit. It could be other things but I wouldn't waste time or money without first checking the Sail Switch. With access it is very easy to pull and check. Certainly brush it clean since lint is usually the issue. Yes, they can go bad but with a multimeter it's easy to do a continuity check in the closed position.

KenSC · 10-21-2022, 01:45 PM

Just a few quick thoughts.

If you have shore power by day then wouldn't you be able to test the power issue while plugged up? IE. if it works on shore power but not on battery alone then its the battery.

Also if it was a bad battery wouldn't this prevent the furnace and space heater from running all night? I would imagine both of these would drain power very fast.

As far as using heater, mine has an option to use electric heat as a source from the air conditioner vents. Not sure if all RV's have this option but if so that might be better than running a space heater.

Matty Rich · 10-21-2022, 02:11 PM

More than likely the sail switch. Very common part that goes bad. Even on. New trailers.

JBM3M · 10-21-2022, 02:13 PM

Quote:

Originally Posted by KenSC

Just a few quick thoughts.

If you have shore power by day then wouldn't you be able to test the power issue while plugged up? IE. if it works on shore power but not on battery alone then its the battery.

Also if it was a bad battery wouldn't this prevent the furnace and space heater from running all night? I would imagine both of these would drain power very fast.

As far as using heater, mine has an option to use electric heat as a source from the air conditioner vents. Not sure if all RV's have this option but if so that might be better than running a space heater.

No do not have the AC with heat.

JBM3M · 10-21-2022, 02:17 PM

Did the power cycle for 5 mins off and re connected.

Battery or shore power problems are the same.

Accessed the one and only side of the unit that I can without taking the unit out. Opened it up in the inspection hatch and only can see the heat exchanger.

Also do have gas to the unit.

Owners manual says something about control board lights, cannot see at this point. Looked in owners manual for location of sail switch, it shows wrong side related to what orientation I can.

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