Furnace Fan Limit Switch Temperature Settings

Step 5 set the temperature on the middle component to approximately 105 to 115 degrees fahrenheit.

Furnace fan limit switch temperature settings.

Furnace limit off setting. An adjustable fan limit controller typically is designed for furnaces operating at temperatures from 100 f to 250 f has a fan off lower limit that can be adjusted from 50 f to 200 f a fan on switch adjustable from 65 f to 215 f and a fan high limit stop set at 200 f. For a general guide set the two lowest ones from the furthest left to 100 and 130 degrees to control when the fan comes on and goes off. The limit is set from the company from 170 will suffice.

This setting controls the furnace s fan. The limit off indicator setting red arrow in our fan limit switch photo at above left is a safety control that will turn off the oil or gas burner if temperatures inside the warm air plenum exceed a safe level. Some people switch the settings a bit but the first setting is the off settting. The setting for high limit should not exceed the manufacturers engineering guidelines for the heat exchanger.

From the factory the fan on is usually set to about 130 f. The third marker should be set around 200 degrees as a safety shut off for the burner. The second setting is the fan on setting this is commonly 120 130. Once the fan limit switch has sensed that the air in the plenum is a suitable temperature usually around 20 degrees above the room temperature it engages the blower fan to distribute air.

The blower will continue blowing until the fan limit switch has determined that the temperature within the furnace has fallen. When the room temperature reaches the thermostat setting the furnace will turn off. The honeywell fan limit control is also a temperature control limit switch. Another limit control switch which is integral to the honeywell fan control is a high temperature control limit switch.

Setting the middle arm at this temperature ensures that the fan will switch on at the correct time when the furnace warms ups. A vid on fan on and off adjustments for the honeywell heat operated fan switch used on furnaces from the 1960s thru the 1980s this video is part of the heati. This is generally 100 degrees f. The fan limit switch tells the blower assembly when it is ok to blow the heated air.

Set the markers to the appropriate settings for your furnace.