Fan Limit Switch Troubleshooting

The furnace filter is clogged and raises the temperature within the plenum prematurely tripping the sensor.

Fan limit switch troubleshooting.

Fan limit switches can be bought at an hvac supply stores or online. This opens the safety circuit and prevents the furnace from heating. If not shut the power off at the breaker panel. 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.

Finding the limit switch in a rheem furnace takes just seconds. 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. Dirty clogged air filters can cause high limit switches to open. And the limit switch should be pulled out.

High limit 200 degrees fahrenheit. Open the access panel and locate the high limit switch. Some control guides call this summer. Where can you buy a fan limit switch.

Problems that commonly occur with fan limit switches include. If there is a serviceman switch turn it off. The blower motor stops working and overheats. Fan limit switch troubleshooting list before you get started check the air filters in the system.

Push the white button in to force the fan to on or manual or always running mode. Pull the white button out to put the fan back into auto mode turning on and off under control of the switch and. 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. Set the building thermostat to call for heat.

To test a limit switch you ll want to check continuity to determine what state the switch is in. However the typical temperature settings are as follows. Step 1 remove the top access panel on the front of the rheem furnace. 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.