Fan Limit Switch Troubleshooting

The switch s sensor becomes dirty and stops working correctly.

Fan limit switch troubleshooting.

Dirty clogged air filters can cause high limit switches to open. The blower motor stops working and overheats. Push the white button in to force the fan to on or manual or always running mode. If the fan limit switch worked normally continue as follows.

Set the building thermostat to call for heat. However the typical temperature settings are as follows. This opens the safety circuit and prevents the furnace from heating. If both the blower motor and limit switch test good than other possible problems may be the contactors circuit board or gas valve and possibly the thermostat.

High limit 200 degrees fahrenheit. Where can you buy a fan limit switch. Fan control limit 90 and 130 degrees fahrenheit. Problems that commonly occur with fan limit switches include.

And the limit switch should be pulled out. Some control guides call this summer. Step 1 remove the top access panel on the front of the rheem furnace. Pull the white button out to put the fan back into auto mode turning on and off under control of the switch and.

Finding the limit switch in a rheem furnace takes just seconds. Fan limit switches can be bought at an hvac supply stores or online. If not shut the power off at the breaker panel. The instructions differ depending on whether you have a combination switch or separate high and fan control limit switches as well as on the specific model you have.

The furnace filter is clogged and raises the temperature within the plenum prematurely tripping the sensor. Turn off electrical power to the heating system reconnect the fan motor where you previously disconnected it turn on electrical power to the heating system call for heat. Open the access panel and locate the high limit switch. If the fan in your furnace runs continuously or turns off and on too frequently you may need to adjust or replace the limit switch.