Furnace problem
I may need to replace the furnace; I really don't know why because it's 'only' 21 years old. Anyway, it's always worked fine but on this trip, it only lights when electricity is available. Unplugged...
Forum Discussion
RustyJC wrote:magic43 wrote:
If your voltage is OK then the odds are that you have a "sail switch" problem.
Going back to the OP's post #1, the furnace works fine when the RV is connected to shore power or the generator. It only fails to light on battery power. Since the fan motor never sees 120VAC, and if the 12VDC voltage supply to the furnace doesn't change irrespective of the power source (i.e., shore power, generator or battery), then the fan motor speed shouldn't change, either. I'm struggling to see how the sail switch plays a part in this problem IF the voltage to the fan motor and, thus, the fan motor speed doesn't change.
Rusty
Because shore/generator power supplies converter which is supplying the DC System.
No AC power than battery alone is supplying DC System
That is why OP needs to check actual DC Voltage with and w/o AC power.
Could be 13.7V when on AC and only 12V on battery
Fan DC motor could run slightly faster on that 13.7V then on battery 12V....make up sail switch/not enough to make up sail switch.
The circuit board is getting DC voltage when on AC but NOT getting voltage when on battery. (Assumption due to no spark----otherwise it would spark)
Fan speed & sail switch are usual suspects when DC doesn't get to circuit board.
Lower voltage/dirty-loose connections/contacts------resistance.
OP........
You can access furnace via outside cover.
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