Sensor conditioner defrost

During winter months many heat pumps will need to go through a “defrost” cycle during operation. Intermittant problem with the air conditioning not working correctly. Depending on manufacturers, the conditions of going into defrosting are controlled by the microcomputer of the unit.

If the defrost thermostat is open and the board initiates a defrost signal the system will not go into defrost. Q. What could be wrong if your central air conditioner blows cool but not cold air and seems to be always running?

Better systems have demand defrost which works via temp sensors and other variable parameters. Of all the heating and cooling systems used in residential applications, the heat pump is the most complex.

During the defrost action, the outdoor fan stops running to allow the coil to heat up as quickly as possible. This ends the 24-volt signal to the compressor contactor and the outdoor unit stops. Immediately after the outdoor thermostat or sensor reaches a certain temperature the system goes back to normal heating mode. My 2004 GMC Envoy vibrates when I turn the air conditioner or heater on . Override Controller based on Arduino Pro Mini328P This version has significant re-coding, including these changes:1) Deadband parameter. The unit is only ~3 years old, the programmable thermostat 2 years.

The output of the sensor then controls the heating or cooling apparatus. The system will vary the fan speed and vent location (dash, floor or defrost) to bring the cabin to the desired temperature.