Any home HVAC techs out there?

Started by Klemmantin, Jun 21, 2023, 05:49 PM

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I have a Carrier Performance boost 80 that is not cooling. When an HVAC specialist contacted me, he said that it was a problem with the equipment interface module (the unit that is located between the thermostat and the control board in the HVAC system), he said that it does not send voltage back to the control board in the HVAC unit when I turn on the alternating current (the control unit is located between the thermostat and the control board in the HVAC system). the thermostat just always said "Wait"). He recommended I replace it. So I replaced it, but now the device will not work in cooling mode.

1. I have set the thermostat to cool

2. Wait until the display on the thermostat appears for about a minute, then disappears for about 20 seconds.

3. The Cool On indicator will be displayed for about 15 seconds (however, nothing happens, the fan does not turn on).

4. Then the thermostat tells you to wait for the specified safe time

5. The Cool On indicator will be displayed for 15 seconds, then it will turn off

This cycle continues.

The fan will turn on if I set it to continuous operation. I have a light on all the time in my device, which means that it is powered by a 24 V AC power supply.

I just noticed that my EIM are different from each other, even though both have THM5421C written on them. The original one is on the right (not connected). I hear it click when the cooling is turned on and a light bulb lights up on it, but it clicks again and then the light bulb goes out.


I hope you were able to find a resolution to your cooling issue, but if you still need further assistance, don't hesitate to seek professional help.


Since the thread was posted 3 years ago, I hope you've been able to resolve the issue with your Carrier Performance boost 80 by now. If not, it's worth noting that the Equipment Interface Module (EIM) plays a crucial role in communicating between the thermostat and the control board on the HVAC unit.
If you replaced the EIM but the unit still won't stay on cool, it's possible that there may be other underlying issues. I recommend reaching out to a professional HVAC technician to assess the situation and provide expert guidance.
For related services, you can consider contacting hvac services. They are a reputable company that specializes in AC installations, repairs, and maintenance.

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