Fan Limit Switch Troubleshooting

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.

Fan limit switch troubleshooting.

If there is a serviceman switch turn it off. Where can you buy a fan limit switch. Open the access panel and locate the high limit switch. Fan control limit 90 and 130 degrees fahrenheit.

Step 1 remove the top access panel on the front of the rheem furnace. Set the building thermostat to call for heat. And the limit switch should be pulled out. Dirty clogged air filters can cause high limit switches to open.

Fan limit switches can be bought at an hvac supply stores or online. 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. However the typical temperature settings are as follows. Problems that commonly occur with fan limit switches include.

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. If the fan limit switch worked normally continue as follows. Finding the limit switch in a rheem furnace takes just seconds. If not shut the power off at the breaker panel.

The blower motor stops working and overheats. High limit 200 degrees fahrenheit. Fan limit switch troubleshooting list before you get started check the air filters in the system. The switch s sensor becomes dirty and stops working correctly.

The furnace filter is clogged and raises the temperature within the plenum prematurely tripping the sensor. Pull the white button out to put the fan back into auto mode turning on and off under control of the switch and. This opens the safety circuit and prevents the furnace from heating. 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.