Originally Posted by garbonz
A normally operating RV (or other) furnace works FINE in Colorado, although an orifice check may help, they don't routinely do a high altitude change, as far as I have been able to tell. What is disconcerting to me is the OP's quote "constantly backfire when running" which indicated it is not just upon ignition. I have seen and experienced water heaters doing that, but not furnaces.
A reputable propane dealer in Ft. Morgan should be able to troubleshoot your issue and if you have been getting a 100lb tank dropped offf, they may be able to do that at no or reduced charge in return for the business. If they think it needs a new orifice, then they may even be able to do that themselves.
Propane is in routine use out here in the mountain west and frankly a RV furnace does not flow that much propane for it to be a problem for a 100lb tank. SOmething else is probably going on.
Your right but you need to start some where and I would with the propane company and let them make sure no moisture is in the tanks. here is a little check list for the OP
D. Burner Ignites But Shuts Off:
1. Check to be certain that flame sensor is over slots in the main burner and that the
main burner flame is burning against the tip of the flame sensor - adjust by bending
the sensor probe. NOTE: Sensor probe should be in the inner blue cone of the
burner flame, approximately 1/4" to 5/16" above the burner.
2. If the burner still goes off and into lockout, check the wire connections at the flame
sensor and the module board.
3. If wire connections are okay, check for continuity through the flame sensor wire.
4. If the continuity of the flame sensor wire is okay, check with microamp meter in
series with the flame sensor and flame sensor wire to be certain the flame sensor is
generating at least seven microamps within seven seconds after the burner is ignited.
Connect the meter as follows: (+) to sensor wire, (-) to sensor probe. Adjust the
position of the sensor probe, check air adjustment and check for carbon deposits on
the sensor probe if the reading is less than seven microamps.
5. When the flame sensor circuit is generating at least seven microamps, but the burner
still goes off and into lockout, replace the module board.
He might not be locking out but that 1 sec can cause the OP problem to. IMO this is past the average TT owner. It's very dangerous. The propane Company should be able to figure this out for him. Haven't heard back so maybe they have it resolved. It would be nice to let people know and check in. They might have just pick up a bad batch of propane with some moisture in it.