Problems with Evcon 7681-8191/2 gas furnace

[keith]

One other thing. If the Centrifugal motor blower is bad, would that cause the gas to shut off early before reaching the thermostat temperature?

The motor sounds fine, it starts up, runs then shuts off. I put a meter to it and coming from the board the left wire read good, but when I connected up to the right blue wire, it would kick to the next cycle. I'm sure you are correct in your assesment, but I am still most curious about the failure to reach the thermostat temp. Please let me know.

Thanks,
Keith

[Robert]

Hi Keith,

Inside the booster motor is the centrifugal switch. When the motor reaches designed speed/rpm's, the contact points in the cent. switch close sending low voltage 24vac signal onward to operate gas valve and burner.


IF this motor is bad or goes bad and the cent. switch does not close or opens early, the low voltage signal will stop and gas valve will close extinguishing the gas flow and the burner.



It could be the motor or the cent switch, but if either of those, the motor has to be replaced.


To be sure of fault, have a Tech come out and test system.



Thanks,
Robert

[keith]

Gotcha. I've gotta call into my normal tech, hopefully I'll hear back from him in the morning.

Thanks again. I appreciate you and the good info you provide.
Keith

[Robert]

Hi Keith,

You're very welcome, glad I could help some.


Since you cannot just replace the cent. switch and have to replace the motor which is affordable, but not cheap, best to know for sure if that is it.


If so, it is a DIY replacement if you choose to go that route.


Take care and best wishes,
Robert