Evaporator motor problem.

[rustrunner]

Neighbor is having problems with the evaporator motor running constantly. It goes at full speed, then will slow slightly and then speed up. But runs all the time, not shutting off. A/C man says it needs new motor. I always thought a motor had to have something to control it's on off running. Why would the motor be bad if it runs?

 

[Jim greengo]

Are you talking about the motor in furnace/air handler?
Something has to be calling for it to run.
Is switch on stat turned to on instead of auto,or tripped limit switch?

 

[rustrunner]

Thermostat is on auto and it's for their a/c air handler. I figure the motor is good, just something controling it is bad.

 

[Wrench97]

ECM motors will do that and they are not cheap.

 

[mikebaker1129]

True $400-800 bucks

 

[rustrunner]

Thanks guys.

 

[nadogail]

My HVAC system has a fan setting where the fan runs constantly to keep the air passing through the filter pulling pollen and dust from the house.

 

[LS6 Tommy]

If it's not running at a constant speed, it's not a fan/limit or t-stat issue. It's an ECM and the ecm board on the motor is most likely going bad...

Tommy