Google nest error 104 now 74.


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Old 06-13-24, 02:27 PM
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Google nest error 104 now 74.

We have had this nest for over 3 years and it always worked fine. Now when we went to start up the air we got E 104. I turned off the breaker and now we get E 74. I checked the compressor fuses and they were good.

Thanks,

Brian

 
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Old 06-13-24, 05:32 PM
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Post a picture of the wiring on the nest...... How to insert pictures.

E104 is typically caused by excessive load as in a short.
E74 means no 24vac power.

It sounds like you had a short on the thermostat wiring and if you didn't blow a fuse... the transformer blew. Typical short location is between the house and the condenser. Animals and weed wackers do a number.

You will need a volt meter to make checks.
 
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Old 06-14-24, 07:49 AM
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Thanks for the reply Pete! Checked transformer and getting 24 volts. Checked stat wires no voltage. Have a friend who is in the business coming over as it appears to be an issue outside with wires, contactor or condensor?

PS Fuse on board is good as are fuses outside.
 

Last edited by sportsdadmi39; 06-14-24 at 07:50 AM. Reason: addition
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Old 06-14-24, 02:15 PM
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You should have 24vac to R and C.
You should measure 24vac between R and G, R and Y, R and W at the stat.

If you need further help... let me know what the air handler is.... model number.
 
 

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