Furnace ECM blower!!

[Plumber69]

Furnace blower runs all the time. Dissconnected thermostat wires, still runs. There's 2 wire harness that go to ecm, ones power the other is communication. With thermostat and communication harness disconnected the blower still runs. So I'm assuming there's a short in the ecm?

 

[WorthFlorida]

Furnace blower runs all the time. Dissconnected thermostat wires, still runs. There's 2 wire harness that go to ecm, ones power the other is communication. With thermostat and communication harness disconnected the blower still runs. So I'm assuming there's a short in the ecm?

Speed control for an ECM motor is usually 0-10v. I cannot find the number for 3.0 ECM motors. It is the back part of the motor is bad. At one time you could just replaced the part but no longer. It has the controls and AC to DC converter.

 

[Sponsor]

 

[Fitter30]

The control module back of motor could be bad. That module can be replaced. You will need brand model, serial and all the motor numbers. Need a service manual on the furnace and with the motor numbers might find the manual just on the motor. There are utube videos on these motors. Ecm motors are not cheap.