Quote:
Originally Posted by nochaos  - the voltage on the inducer is ALWAYS around 120V. The reason I am highlighting the above is that it is supposed to drop to 24V after the gas is burning, transforming itself in a flame sensor. |
I'm presuming you meant that the voltage on the ignitor is remaining at 120 VAC?
Does the HSI remain red or white hot after the burner lights?
Not too many furnaces use the ignitor as a flame sensor, and frankly I wasn't aware that the voltage was supposed to switch to 24 volts after the ignitor high voltage switched off.
Sounds like the ignition module would have a SPDT or DPDT relay that switches on to heat up the ignitor and after the period for the ignitor to heat the relay would then change state and apply the 24 volts you say should happen. If so that relay doesn't sound like it's working reliably.
Going back to your first post, the problem appeared to be that the 120V was not being switched on to the ignitor. Perhaps that was the same sticky/defective relay but instead of not applying 120V perhaps it was only applying the 24V.
--I don't suppose you tested the voltage being applied to the ignitor on that occasion?
So my assessment is that both the problems you have observed might well be caused by the same sticking/defective relay.
Often a way to test or confirm such a theory is to tap on the ignition module to make it easier for the relay to change state. The handle of a screwdriver makes a good tool for that.