My HVAC Unit Is Causing Strange Voltage Readings on the Panel

Low Refrigerant

• Low refrigerant is not often considered to be an electrical problem, but it may be the cause of the voltage readings you are finding. This occurs when a safety control inside your air conditioner senses that you are low on refrigerant, probably because of a slow leak. It will then shut down power to the contactor on your system, while still allowing power to flow to the transformer and other areas. You can refill your system with refrigerant and solve leaking problems to restore normal functions.

Relays

• The relays in your HVAC systems are the contactors that switch on in order to complete a circuit and start HVAC operations. These relays and the circuits they control should be at 24 volts of AC current. If they are not, and if you are not getting the same readings at your thermostat panel and transformer, the problem could be a failed relay that has burned out and needs to be replaced.

Wiring Problems

• Sometimes the issue is in the wiring itself. Failed wiring that stop current from reaching circuits entirely, which can lead to power in once section of your system but not in the panel. Wires needs to be inspected to locate the damage, so they can be replaced to restore current in your system. Examine the wiring leading form the panel controls to the thermostat and your relays.

Thermostat Issues

• The thermostat itself might have an electrical problem. When this occurs, it can send errant signals to the control panel or stop operation entirely. Your system might be working correctly but not have current coming from the thermostat to the control panel, which means you need to inspect your thermostat itself for failed circuitry and power problems.