PDA

View Full Version : How do I test the induction motor on a lennox g40uh


4giants
Nov 20, 2015, 05:37 PM
My old furnace finally crapped out got a used Lennox g40uh furnace hooked it up and it won't turn on the 2 LEDs are slow blinking which indicates everything's normal the manual says the induction motor is supposed to come on first its no need to find out how to test it

ma0641
Nov 20, 2015, 06:59 PM
Remove the black lead from the inducer motor at the control board. Call for heat. Measure the AC voltage from the induced spade connection to neutral spade. If you have 120VAC,and the motor is not turning, the motor is probably bad. With no voltage it is somewhere else.

ma0641
Nov 20, 2015, 07:08 PM
[QUOTE=ma0641;3754019]

QUOTE]
Did it run through a diagnostic purge test first? Normally, when first started up, the air handler fan will run, system checks itself and then turns off. Then, it will start cycle. Inducer, pressure switch, igniter, gas valve. Check this, remove the black lead from the inducer motor at the control board. Call for heat. Measure the AC voltage from the inducer spade connection to neutral spade. If you have 120VAC,and the motor is not turning, the motor is probably bad. With no voltage it is somewhere else.[/

4giants
Nov 20, 2015, 07:49 PM
The furnace didn't do the diagnostic purge self test. Both green LEDs blink slow

ma0641
Nov 21, 2015, 08:21 AM
That is a normal code for Lenox. Did you test for voltage at the inducer when calling for heat? You have to start testing somewhere. Batteries OK in the thermostat?