Having problem with furnace blower not shutting off after cool down cycle. Failing maybe one in ten cycles. Hydro Flame system in 93 GV.
Here is some troubleshooting sources that may help.
Troubleshooting RV Furnace Problems (http://www.beamalarm.com/Documents/troubleshooting_rv_furnace_problems.html)
Any common thread as to when this happens-- perhaps when batteries are low?
And it never hurts to open the outside access door, and with the furnace off, to unplug the gang connector from the PC board and clean it with De-Oxit or other cleaner so you know the contacts are clean.
Brett
Brett
My rear furnace did the same thing recently. It just would not shut the blower off.
I replaced the fan relay which is located on the blower cover on the right side as you are facing the open furnace. Cost about $30, held by two screws and has four push on connectors.
As Brett suggests, I cleaned every contact while I was there and resprayed with CorrosionX.
Thanks for input. Was on shore power. Reseated pcb connectors, but no cleaner. Where did you purchase relay?
Obviously a low battery wasn't the issue here but was mentioned by Brett. I will add to that thought for future reference by saying that unplugged from shore power my front furnace wouldn't cycle. Flame would go out and the blower kept blowing COLD air. Rear furnace cycled fine. I plugged up shore power and both cycled fine. I left charger on for a while and the front resumed proper cycle. Appears a battery charge issue but it was odd to me why the rear furnace wasn't fazzed. Will add that coach batteries were at 11. 9. at the time.
Dub,
The longer wire run from 12 VDC breaker box (at least ours is under the front edge of the queen bed) to the front furnace may offer just enough additional voltage drop that voltage at the front furnace is inadequate. You can easily check this with a voltmeter-- check at front furnace when working properly and then when "misbehaving".
Brett
Brett, I bet that is the case.
If so, and your generator is located just below the front furnace is to use a large gauge wire (10 gauge or larger) from the starter lug on the generator to the furnace. The wire from battery to generator is a LOT bigger than would be reasonable for you to pull even if you were willing to run a large gauge wire from breaker box.
Be sure to put an in-line fuse at the generator end to protect the wire.
Brett
I also had a similar experience recently. When the furnace blower came on you could hear the flame ignite for a few seconds and then the fan would just keep running. My initial diagnosis was a bad electronic igniter/thermocouple. I had the part replaced for about $150 but no improvement. Finally took it to an authorized Atwood technician. It turned out to be the regulator at the propane tank was not putting out enough gas to keep the flame going. Put a new $30 regulator on and now it is fine.
Sometimes self diagnosis ins't the most economical way to go. Camping world offered to do the diagnosis before putting the thermocouple on but I thought I was smart enough that I didn't need to spend the additional $75 so I wasted $150 for the part and labor.
But still Kent, I don't think you needed to be kicked in the ribs for trying
Every day is a learning experience.
Think of how many times you were right in your diagnosis and did not pay the $75. You are way ahead. :)
Besides the $150 part was getting ready to fail anyway & you diagnosed it just in time.
You were smarter than you thought 8)
Barry, thanks for the emotional support. I only feel half as dumb now!!!!
Then you are half way there. ??? ::) :)
We had the same experience you are having at two different times.
The first time, it was the "plenum over temp switch at the most inboard part of the furnace.
The next time, I took it to an RV dealer and replacing that part did not cure the problem.
He said he had a machine that would "test" my electronic circuit board and see if that was the problem.
When he came back the board indicated to be bad and a new one was installed and the furnace worked.
Reputable dealer but, I did not have the opportunity to see the board tested. Maybe someone else has seen one tested.
It was mid October in Lansing, MI and I needed heat NOW! I paid the $400 bill and drove away.
The next night (on the road) the blower wouldn't even turn on and nothing was doing anything. Na Da. Zip Zero.
I was upset as you can imagine until I diagnosed that the "circuit breaker" (the only one in the fuse panel-rest were glass fuses) was tripped.
Reset the circuit breaker and the furnace fired right up. Haven't had a problem since.
I still have the old circuit board and if and when I find someone with a board tester, I will get it tested after I examine it with a loupe and see if there are any cracked solder joints.
Regards,
After completing my previous post, I thought about the situation and after some research found some info that may be of help to you.
http://bryantrv.com/docs2/docs/hflamefurn04.pdf (http://bryantrv.com/docs2/docs/hflamefurn04.pdf)
Looks pretty comprehensive and I will I would have found it in October.
Regards,
Jon, if your coach is like mine you have a circuit board tester. You can always hook up one circuit board to the other furnace. They are easy to remove, one screw, and they are identical on my coach. You could even unplug the new circuit board and plug in the old one then turn on the furnace and see if the old board works. FWIW
I'm disadvantaged. I only have one 30,000btu furnace.
Regards,
JON TWORK KB8RSA
That shows what I know. I thought they all had two furnaces or an Aquahot. Can you still check out the old circuit box by hooking it up to the furnace like you can in mine?
I have no idea about hooking it up to the furnace but, apparently certified dealers have a black box they can use to test the board. I just installed ports for a couple of catalytic heaters in the coach. One is a 3000btu unit and the other is a 10,000btu which may end up being too big. Not sure. May add a 6000 catalytic. The big unit is a ceramic radient unit.
Regards,
JON TWORK KB8RSA