My Nest thermostat has been pretty reliable for a few years in controlling my heat pump. The other day I turned on the AC and it would blow only warm air, even though the Nest says cooling is on. I have not changed a thing. I restarted the Thermostat but that didn’t help. So I assume it’s either the Nest or circuitry internal to the heat pump. Before I call a service tech, is there any diagnostic I can run to tell me where the problem is?
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Thanks for reaching out and we're sorry for the delay.
Let's try the following before calling your HVAC technician:
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