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Tim H.
Tim H., HVAC Professional
Category: HVAC
Satisfied Customers: 3971
Experience:  Experienced in all aspects of HVAC, both residential and commercial.
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When we turn our system switch to off the fan still comes on

This answer was rated:

When we turn our system switch to off the fan still comes on from time to time.

Tim H. :

Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Thanks for the opportunity to help!

Tim H. :

Hello there

Tim H. :

Are you there?

Customer:

What is your answer

Tim H. :

I need more information. What is the make and model of this furnace?

Customer:

Honeywell modelTH4210D1005 0732

Tim H. :

That is your thermostat. I need furnace make and model

Customer:

ARI Mode EIRD036S06B

Tim H. :

The model number should be on a tag inside the top furnace door. The reason I ask for this is in case I need a wiring diagram. The ARI number is XXXXX the model.

Customer:

This # XXXXX on outside of furnace which sits outside and has no easy door to get into.

Tim H. :

OK, so this is a package unit correct? Approximately how old is it?

Customer:

2007

Tim H. :

OK

Tim H. :

There are 2 possible reasons why the fan may kick on occasionally with system switch in the off position: a bad thermostat or a bad control board.

Customer:

okay I will try to find somebody to look at it. thanks

Tim H. :

If you take the green wire off the G terminal at the furnace board and this still occurs, that would tend to eliminate the thermostat as the culprit

Customer:

I probably shouldn't play with wires etc.!!!

Tim H. :

OK, I understand. LOL

Customer:

Thanks

Tim H. :

Sometimes a thermostat can be faulty and send a signal to the board causing fan to come on. Other times a bad board will do that

Customer:

I think you have done all you can from where you are. Thanks

Tim H. :

Yes, good luck! Thanks for using Just Answer and please don't forget to rate my service as that's how experts get paid (bonuses are always appreciated). Feel free to post back with any additional questions. Have a great day!

Tim H. and 3 other HVAC Specialists are ready to help you

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