Hello and Happy New Year... We have about a 15 year old Day + Night furnace that only the blower comes on with no heat... Is there a way to test the limit switches? There is 4 of them in the furnace.. There is a small square button in the center of all of these switches.. I wanted to test these before we buy a circuit board... Thank you so much for any response...

Do you have an electrical multimeter?

There is a small square button in the center of all of these switches..

Push the button in. If the switch is tripped pushing it in will reset it. Otherwise you can jump each switch out one at a time. If it starts working you cannot leave it jumpered since it is a safety device and must be replaced before you wuse the furnace.

Posting a EXACT model number would be helpful.

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Originally Posted by MarkwithaK

Do you have an electrical multimeter?

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HI and Thank you for the response.. Yes I do have a multimeter..

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Originally Posted by maiden usa

I know nothing about this stuff, but eventually someone is going to suggest that you clean something called a flame sensor. I just thought I would tell you so you wouldn't be caught off guard.

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Thank you and I will clean that with sand paper..

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Originally Posted by hvac1000

There is a small square button in the center of all of these switches..

Push the button in. If the switch is tripped pushing it in will reset it. Otherwise you can jump each switch out one at a time. If it starts working you cannot leave it jumpered since it is a safety device and must be replaced before you wuse the furnace.

Posting a EXACT model number would be helpfull.

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HI.. The model is 376CAV060095 Thank you for the response...

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Originally Posted by stummped

HI and Thank you for the response.. Yes I do have a multimeter..

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Can you tell me how to check them with the multimeter.. Thank you again for any response...

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Originally Posted by stummped

Can you tell me how to check them with the multimeter..Thank you again for any response...

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Set the meter to measure voltage and apply probes to both sides of switch. If you read 0 volts, move on to the next one. If you read voltage (approximately 24v.) the switch is open.

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Originally Posted by KC13

Set the meter to measure voltage and apply probes to both sides of switch. If you read 0 volts, move on to the next one. If you read voltage (approximately 24v.) the switch is open.

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Thank you KC... I will put the meter on them.. Is this OK to do with the blower motor running? Thank you again for your response...

Yes, you need the system powered to perform this test.

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Originally Posted by KC13

Yes, you need the system powered to perform this test.

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Thank You Very Much KC... I will give it a try..

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Originally Posted by stummped

Thank you and I will clean that with sand paper ..

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Did someone say flame sensor?

Now that is just gratuitous. I would expect that sort of thing from Hollywood, but you? :D

Did someone say Hollywood ? Lets go visit Granny.

773H yeah! Swimmin' pools, movie stars!

Thanking you kc, hvac1000, mark with a k and maiden for all your help... It works now..

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Originally Posted by stummped

thanking you kc, hvac1000, mark wih a k and maiden for all your help... It works now..

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Good deal I new we were good for something. Stay warm.

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Originally Posted by hvac1000

good deal i new we were good for something. Stay warm.

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You folks are awesome!!

What was the solution??