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rsator · May 13, 2007, 07:29 PM

I have an all electric home. Lately, when the A/C is set to run, with fan on auto, the compressor can be heard coming on, but the blower fan does not come on. If I use the temperature set switch to set the temp higher, and wait a couple of minutes, then turn it cooler again, it will usually start like it is supposed to. I am assuming there is a switch at fault, but which one and where is it? Any help will be greatly apprciated.

hvac1000 · May 13, 2007, 08:42 PM

Sounds like the A/C blower relay coud be at fault. A model number of the furnace and brand name would be of help.

rsator · May 14, 2007, 04:46 PM

Originally Posted by hvac1000

Sounds like the A/C blower relay coud be at fault. A model number of the furnace and brand name would be of help.

Goodman Manufacturing Company of Houston, TX and the model is CK42-10.

Thanks for your interest and help.

rsator · May 14, 2007, 04:47 PM

Originally Posted by rsator

Goodman Manufacturing Company of Houston, TX and the model is CK42-10.

Thanks for your interest and help.

PS - this problem does not occur all the time, but does so fairly frequently.

Thanks, Robert

hvac1000 · May 14, 2007, 04:57 PM

Your relay will be inside the air handler. I would replace that relay to start with. There are many places on the net that you can order from by model number. The relay is the cheapest component to try first. Unless you have the meters to test it I would just say replace it.

hvacservicetech_07 · May 14, 2007, 09:10 PM

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rsator · May 14, 2007, 09:15 PM

Originally Posted by hvac1000

Your relay will be inside the air handler. I would replace that relay to start off with. There are many places on the net that you can order from by model number. The relay is the cheapest component to try first. Unless you have the meters to test it I would just say replace it.

I have a multi-meter, and use it often. Am I looking for resistance, continuity? Should I check it when it is off, running, trying to start? Is it actually better to just order the relay? Can you provide a suggested web site for ordering the relay? Thanks very much for your information and assistance.

hvacservicetech_07 · May 14, 2007, 09:22 PM

What is the model of the furnace?

hvacservicetech_07 · May 14, 2007, 09:24 PM

The relay is pretty simple, the stat sends 24 volts through the "G" terminal to the relay it pulls in the contacts and sends high voltage to the blower.

rsator · May 14, 2007, 09:45 PM

Originally Posted by hvacservicetech_07

The relay is pretty simple, the stat sends 24 volts through the "G" terminal to the relay it pulls in the contacts and sends high voltage to the blower.

The Goodman web site, for model number CK42-10, liss the Time Delay Control Relay for Blower for $142. Is that about the price I should I expect to pay? It also lists the Fan Relay for $132. I sure hate to spend that mcuh money not knowing for sure which relay I need.

hvacservicetech_07 · May 14, 2007, 09:52 PM

WoW, that seems a little high to me, The only way that your going to find out if it's bad is by testing the relay when the blower doesn't come on, locate the relay and find where the 24 volts hooks to the coil on the relay, make sure you have 24 volts there, then check and see if you have voltage leaving the relay and going to the blower motor. If your not able to figure this out you may want to contact a pro, this can be very dangerous if you are not sure what you are doing.