Hvac Fan Relay Troubleshooting

As a result electric power to the fan motor doesn t stop and the fan continues to run.

Hvac fan relay troubleshooting.

The relay will usually be activated once it is detected that the vehicle s temperature approaches excessively high temperatures. The blower motor is crucial to the proper functioning of your hvac system. Ac contactors can wear out and are at the top of the list of common air conditioning service failures. One of the most common problems with furnace fans is a bad blower relay.

The purpose of the fan center relay is to provide a low voltage control 24 volts to control a relay that can be used to control two speed blower motors and auxiliary circuits in heating or cooling equipment many of the newer furnaces do not have fan center relays but many of the older furnaces and some new furnaces still do. An ac contactor is a 25 mechanical relay that uses low voltage power from the thermostat to switch 220 volt high amperage current to the compressor and condenser fan. If there is a battery check if it is working properly. Steps you can take to identify a problem with the ac fan.

The cooling fan relay is the relay that controls the engine s cooling fans. If no voltage is recorded you will have to replace the board or the relay. A bad relay fan sequencer relay fan limit control or circuit board with contacts sticking this depends on the type and age of the furnace a problem with the limit switch or a problem that is causing the limit switch to open. When a relay becomes stuck the circuit remains closed.

If the ac fan motor is bad or the capacitor is faulty you. Purpose of the fan center relay. The first thing to do is check the relay or voltage from the board. The blower motor relay is a small but vital component in all hvac systems.

This video will show you how to properly diagnose your blower by using the multime. It s a frustrating experience to turn on your furnace only to discover no heat comes through the vents. This is another common reason behind faulty. When troubleshooting efforts point towards a compromised relay a simple replacement job quickly brings your systems back online.

When the correct parameters are met a temperature switch or the computer will activate the relay which will allow power to the fans. Relays are what open and close the electrical circuit in an air conditioner.