[aegisc]

I am coming to this forum to get some help on a strange problem of my furnace.

Furnace stopped working the other day, it is a HEIL H8MPT100F14B1 two stage gas furnace, built in 2006.

Inducer motor simply does not start.:vs_mad:

Circuit board blinks three flashes, code is Low Pressure Switch open when should be closed.

first changed both pressure switches, same problem;
second, suspected relays, got new circuit board, connected everything exactly the same as before, still the same three blinks.

With multi-meter, measured W and C, 27V AC, so no problem for thermostat or thermostat wiring;
measured C and R, 27V, so transformer is working;
measured 115V output port for the inducer motor, found no voltage at all.:vs_mad:

What could be the problem? I have brand new board and pressure switches.

 

[roughneck]

So you did or didn't find voltage at the inducer motor? The way you wrote it is confusing.

 

[HVACDave]

Check for 120V at output of board to inducer fan, make sure inducer spins or is not seized up. then check for voltage at inducer once wiring is reconnected to board (assuming you had 120v at board terminals). Maybe wire is broken, connector is no good, motor is seized or burned out, If motor is shorted may have cooked terminals on board, could be a variety of things.

 

[aegisc]

no voltage from the board to the motor.

So you did or didn't find voltage at the inducer motor? The way you wrote it is confusing.

 

[aegisc]

I can spin inducer, it is not seized up.
There is no power on the board terminal.

Check for 120V at output of board to inducer fan, make sure inducer spins or is not seized up. then check for voltage at inducer once wiring is reconnected to board (assuming you had 120v at board terminals). Maybe wire is broken, connector is no good, motor is seized or burned out, If motor is shorted may have cooked terminals on board, could be a variety of things.

 

[beenthere]

Did this new board happen to come from Ebay.

 

[aegisc]

no, it is from authorized part supplier

Did this new board happen to come from Ebay.

 

[beenthere]

Post pic of the wiring on the new board. Sounds a bit like the board may not have 120 volts to it.

 

[supers05]

Double check the wiring to the board.

Cheers!