Our stern small guy was re-built in 2001. It's getting cooler here at 5k, so I fired the rear yesterday morn. Fan came on, heard the "click" (sail switch?) but no heat! Shut it down, pulled all the wire connections to check for tightness, etc. Yes!, it fired heat, I was so proud. Proud until this morn, when it did the same thing. I've got a spare card on board, looks to be easy to replace, or do I have "deeper" problems? Thanks, M
Mike,
When it fails to heat is the igniter clicking? Is the gas valve opening (12 VDC to it? propane smell in exhaust?)?
I hear the "click", will check for power at the gas valve, no smell. Not too sure why it worked after dinking with the wires, though. If we still lived up north in the "green & grey" where the furnaces get heavy use, I'd prolly pull it, but this is a "Southwest" coach.
What I have found many times is that there small bugs that crawl in through the orfice and then this creates a blockage not allowing gas to flow through. You would have to remove the burner and solenoid assembly and clean out the orfice, I think that it screws in to the pipe from the solenoid.
We've had "mud daubbers" get into previous furnaces, and the after-market screens worked fine. (even though Suburban voids warranty if used) This problem is different. ???
Not mud daubers, tiny nats that get into the orfice and plug it.
I found spiders in the tube and orifice in our furnace.
Still doth not explain why it did not work, then worked, then did not work, all in a 24-hour period.
Manual with some trouble shooting tips:
http://bryantrv.com/docs2/docs/hflamefurn04.pdf
Old thread from when I rebuilt our furnace. Has some tips from other members on what can go wrong:
Need Hydro Flame Furnace Burner (http://www.foreforums.com/index.php?topic=23119.msg178703#msg178703)
I recall the connections to the circuit board causing issues. The circuit board location is such that they do see some weather. One "unplug" and "plug" might work for a day but cleaning the connections should last longer. I use dielectric grease to keep corrosion at bay. If you decide to replace the circuit board (and I'm not saying you need to) the aftermarket Dinosaur Electronics brand is good. I have one in one of the two furnaces in our coach. The other OEM board is still working fine.
I have replaced the burner assemblies on both front and back furnaces of our 1995 U280. They rust thru and the propane/air mixture fails to burn correctly. I used the newer part numbers that are available.
You might try tightening the plug that plugs into the board by using a small screw driver to press on the connectors in the plug. use dielectric grease after tightening. this solved my problem when my furnace was intermittent.
Bill
That's pretty common, Mike. I've had two furnaces that did the same. I recommend you clean all the connections and replace the board. It will likely fix the problem and if it doesn't you'll have a nice shiny board to admire every time you open the furnce compartment.
jor
Do you have two heaters?
If you do swap the control boards to see if the problem moves to the other heater.
Ditto on reply #12. Get some good contact cleaner and plan on checking at least annually.
CAIG Laboratories: DeoxIT & More at DX Engineering (http://www.dxengineering.com/search/brand/caig-laboratories-inc)
These guys make good stuff.
When the propane has been shut off from mine for a long period of time I have to recycle the on/off switch of the thermostat a bunch of times but it always does light. Sometimes 20-30 times. I listen for the second click which is the igniter. If I don't hear a second click I turn it off and back on again.