My AC won't come on and the fan won't start unless I push in the reset button on the furnace's high limit switch.When I push in the button, it runs continuously, but still no AC or heat.
At first, it tried to run but it chugged like it was being turned on and off really quickly, then it finally quit.

What I have tried:

1. Turn Fan switch on stat to "Auto" (nothing)
2. Turn Fan switch on stat to "On" (nothing)
3. Tried another stat that I had laying around (nothing)
4. Jumped red + green wires on back of stat (nothing)
5. Tested motor (wired direct - works fine)
6. Pushed reset button on limit switch in (motor runs continuously)
7. Jumped red + green contacts on relay (nothing)
8. Cleaned contactors on AC unit (nothing)

We had the limit switched replaced a few months ago. I have a feeling that the problem may be with the relay.
Is there anyway to bypass (or test the relay) so I can at least see if the AC compressor comes on?

My AC unit is a Janitrol 018 Condenser (approx 14 yrs old)
My furnace is a Clare Hecia (Clare Bros) that was probably installed when the house was built back in the 1970's.
The relay is a White Rodgers 8a05A-101

Any help is greatly appreciated.

Thanks,

- Vann.

http://www.who-sells-it.com/images/c...t-Vol_0222.jpg

Here is a pic of the W/R relay you are talking about. The relay is used for many different types of control setups

Does your furnace have a circuit board?
What is the exact model of your furnace?

I hope your wiring setup is better than this one.


http://i290.photobucket.com/albums/l...ywellrelay.jpg

Seems the W/R control was made for use in Canada also.

http://www.white-rodgers.com/wrdhom/..._06_pg0094.pdf

Quote:

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Originally Posted by hvac1000

I hope your wiring setup is better than this one.


http://i290.photobucket.com/albums/l...ywellrelay.jpg

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Thanks for the reply. I don't see a picture of the wiring you are talking about, but the way it is wired in my furnace looks like a dog's breakfast.

Sorry - I don't know the model number of the furnace (I am not at home right now)

Is there any way I can test this regulator? I have a voltmeter, but I am not sure what I should be checking (or how to do it). I do feel comfortable wiring in a replacement if necessary.

Actually that wiring job looks pretty similar.

I just had an electrician come in and check the wiring. He changed a couple wires and now everything works. He figured that it was wired wrong and somehow burned some contacts out of the relay (something about wired for a two speed motor - mine is 1 speed).

Anyway, my relay is humming now so I've got a new one ordered to replace it and then I think I will be all set.

Thanks for the replies.

- Vann

Glad you got it going