reznor blower not coming on... help!

[thammel]

I have a reznor udas; been working great for about 6 years. About 2 weeks ago I went out and it was running but garage was not being heated. The led was flashing 3 times and blower was not running. 3 flashes means either limit switch or flame rollout switch is open. They are wired in series. So I replaced the limit switch; this did not fix it. I'm thinking the problem may be that the blower is not coming on. Do you HVAC guys have any suggestions? I guess I could try running the blower motor independently to check it out. The unit is heating up; that is not the problem.

Thanks for any suggestions!
Tom

 

[LS6 Tommy]

If the burner is running, it's not any of the safeties. If you apply power directly to the motor and it runs, it's most likely the control board.

Tommy

 

[BD1]

Check wiring diagram. Burner heats up and then fan starts. Same as a typical home furnace. There maybe a bad sensor


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[LS6 Tommy]

Check wiring diagram. Burner heats up and then fan starts. Same as a typical home furnace. There maybe a bad sensor


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The UDAS series doesn't have a fan stat. The main control board starts the fan 30 seconds after flame prove.

Tommy

 

[thammel]

Well, the problem turns out to be the blower motor. tried driving it directly off 115 and it didn't turn. Took it down and the bearings (sleeve) were binding. Took the motor apart and oiled things up and it now runs. But I ordered a new motor anyway. So I think that is the entire problem.

Thanks for the suggestions!
Tom