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My RUUD furnace blower is not turning on. The circuit board…

My RUUD furnace blower is...
My RUUD furnace blower is not turning on. The circuit board says its a "Limit Switch Open" error. How can I fix this?
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Answered in 2 minutes by:
12/28/2017
Rick
Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 24,846
Experience: 40+ yrs. experience as a licensed oil & gas technician.
Verified

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. First I’ll need some more info so I have a more complete picture of your situation.

The limit error is likely due to the fan not running. I need the model number of your unit. It's on the BTU rating tag inside the burner compartment. Do you have a multi-meter?

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Customer reply replied 8 months ago
I have a multi-meter. I'll get the model #.
Customer reply replied 8 months ago
UGDJ-15EARJR.I did check for voltage across the black and white leads to blower and got 0vac
Customer reply replied 8 months ago
The blower will run if I bypass the circuit board.

Did you check after the burners had fired up?

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Customer reply replied 8 months ago
No change. I hear a click that I would guess is the relay, but it never turns on.

You should have power to main blower 20 seconds after the burner fires up

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Customer reply replied 8 months ago
that's when I hear the click, but no blower.

Then you need a new board if you have no power to the blower 20 seconds after the burners fire up

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Customer reply replied 8 months ago
Ok. What about the flash code for the Limit Switch Open. Is that a symptom of a bad board, or should I check the limit switch?

Like I said earlier, if the blower doesn't run the heat exchanger over heats and will trip the limit

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Customer reply replied 8 months ago
Ah, that makes sense. The limit switch is overtemping because of no airflow from the blower, right?

Yes

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Customer reply replied 8 months ago
Alright, time to track down a board. Thanks.

You're welcome.

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I'd appreciate a favorable rating

Rick
Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 24,846
Experience: 40+ yrs. experience as a licensed oil & gas technician.
Verified
Rick and 87 other HVAC Specialists are ready to help you
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Customer reply replied 8 months ago
Can do.

Thanks

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