Thermostat says wiring needs changed, won’t turn on AC compressor.

[Dferg]

The thermostat has been saying for a few days that the wiring needs to be updated but it’s been installed for years with no issues. Saying there is an issue with the Y1 wire. Now the system randomly today won’t kick on the outdoor AC compressor so the fan is just blowing hot air. I’ve cut power but not done a hard reset yet. What should I do, house is 80 and rising?

[EdmondB]

Hello Dferg,

I’m sorry for the trouble this has caused you, let me help you out. Just a few questions: Have you checked if the Y1 wire is properly connected on the base? Do you have a voltmeter? If so, have you checked the Y1 wire and RC/RH wire  if it's getting at least 24 Volts using a voltmeter? 

Here are the steps on how to use voltmeter.

1. Set the dial to 200 VAC. If the multimeter doesn’t have a 200 setting, choose 100 or 250 VAC.

2. Place the black lead on Y1 Wire  and red lead on RC/ RH wires being tested from the transformer.

3. The normal readout should be somewhere between 20 and 30 V (24 V is most common).

I look forward to your response.

Best,
Edmond

[EdmondB]

Hi there,

Checking in to see if you still need help. Let me know if you have additional questions.

Best,
Edmond