Carrier A/C blower relays clicking


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Old 06-04-16, 06:45 PM
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Carrier A/C blower relays clicking

Hi all having a problem with my carrier furnace/ A/C . Turned a/c on for the first time this year, out side unit runs good, blowing cold air for about 15 mins , then blower relays on furnace start clicking, shutting blower off and on repeatedly till they overheat and reset. Then blower starts and this keeps going on clicking. I replaced circuit board with a new one. board model number HH 84AA 020 . After replacing board it's still doing the same thing. Outside unit never turns off while blower relays are dropping out.
 
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Old 06-04-16, 07:15 PM
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Are relays 24v or 115v coils? If 24v, check transformer voltage and make sure it is outputting ~24v. If its too low, transformer could be weak and not supplying enough voltage. Or coil in relay is NG.
 
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Old 06-04-16, 11:16 PM
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Carrier blower relay clicking

Thanks for reply took a close up of relays . Where would I test transformer?secondary terminals. sec -1 and sec-2 ? The Second board I installed was brand new, with same results. With my volt meter I got black lead on white common and red lead on sec 1 terminal holding at 26.7 volts ac . Is that correct? I checked sec 2 terminal with no voltage when unit is running.
 
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Old 06-05-16, 04:15 AM
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A low voltage short can cause similar symptoms.

Does this occur if you turn off cooling and try to run only the fan?

Another test would be to bypass the thermostat.
The R wire is 24 volt power.
The G wire is fan.

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Removing the thermostat and twisting the R wire with the G wire should run the fan without this clicking if the problem is only the thermostat.

Do not accidentally touch the R wire to the C wire or it will pop the 3 amp fuse in your picture.
 
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Old 06-05-16, 08:31 AM
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Carrier furnace blower relay clicking

Thanks for reply after reading your advice about bad connections . I noticed the person who installed the unit used wire nuts to splice a section of wire to the board. So I soldered the connections to remove that as a possibility. If it's still doing it I will try the blower off auto. And your bypass trick . Thanks again nitro1
 
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Old 06-06-16, 04:19 PM
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Thumbs up Carrier A/C blower relays clicking

Thanks to all for the help. you guys saved me a lot of cash ! I checked the transformer for a voltage drop on the secondary it was holding steady at 26 volts. So I checked the thermostat for for a bad connection, the blower did work in the on position opposed to the auto setting. So I cleaned the contacts on the old school dial , and it seems to be working . Great fourm Thanks Nitro 1
 
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Old 06-06-16, 07:49 PM
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A new thermostat would be cheaper than a service call.

I usually recommend Honeywell 5000 series or higher for reliable operation.
 
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Old 06-07-16, 03:19 PM
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Thumbs up Carrier A/C blower relays clicking

Thank you houston204 you rock ! Honeywell 5000 it is
 
 

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