When it's cold, switch on the thermostat for heat. Blower comes on but not the heater. If the engine is turned on and runs for about 3 minutes, turn off, switch the thermostat to heat, the heater comes on. if you turn the heat off and then on, again, it won't come on unless you run the engine for some minutes. This does not happen if it is warm outside. ??????
marceyo, this may be considerably easier for the talent here to help you with your situation if you added some critical pieces to the puzzle: Year of the Van?, DIY or Sportsmobile build?, gas or diesel?, heater is propane or diesel (Espar)?
FYIW: Since you didn't mention anything about "error codes" being displayed, I would tend to agree with tortorelli that the house battery may be the culprit.
If you're talking about a "standard" Suburban propane furnace with blower, low voltage will prevent the burner from igniting even though the fan starts. Does the sound of the blower fan increase (i.e. RPMs increase) significantly when you start the rig? That would indicate increase in voltage on low battery. Does heater work when you're plugged in on shore power (assuming you have battery charger as part of shore power setup)?
If you're talking about a "standard" Suburban propane furnace with blower, low voltage will prevent the burner from igniting even though the fan starts.
There is something called a "sail switch" who's purpose is to insure adequate air flow to purge the burner chamber of any left over propane prior to ignition and to insure adequate air flow through the chamber to prevent overheating. Low battery voltage can reduce the blower motors speed, thereby reducing air flow to a point below where the sail switch will close. If it remains open, no ignition will take place.
I had 12000 BTU that was acting the same way. Although low voltage would be the first thing to check I know I had adequate voltage and was never able to resolve the problem. I replaced it with a model RP-16NQ core. This 16000 BTU core fits in the same housing box as the 12000 BTU(appeareantly no longer made). The core I bought was substaiousnsly cheaper than the whole unit.
Another thing to check would be the flame box. It accumulates a lot of dust and I expect it should be periodicly cleaned. If it is a Surburban and you do decide to replace it I am happy to provide you with some of the intricacies of a new install'. johngriffith165@hotmail.com
I’m very curious to hear how this plays out. I have the original Suburban propane heater in my 97. It’s been serviced multiple times in the ten years I’ve owned it but it seems that the colder the weather the less likely it is to ignite. On warm days it fires up first try. Temps in the 40s or 50s it usually takes at least three cycles. Once it’s in the 30s or below forget about it. Battery voltage is definitely not an issue. I’m sure I could have and probably should have replaced it for the amount of money I’ve spent.
I recently went though my Suburban furnace to clean it up get it working as best I could.
This place sells tune-up kits for these furnaces. You can also find parts lists and service manuals there as well.
AWOL
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