Gas Furnace Pressure Switch Open With Inducer On

Furnace pressure switch troubleshooting.

Gas furnace pressure switch open with inducer on.

I recently had my natural gas turned on after being off for a few months. If you get a pressure switch code and the inducer will not come on remove one of the wires from the pressure switch. A gas furnace pressure switch is a safety component that makes sure gas is being vented from a furnace before starting. I don t see a flame in the aperture nor do i smell the gas.

The board first checks the switch to ensure it is open prior to inducer call. When a furnace turns on one of the first components to start is the inducer motor. When the pressure switch opens the gas valve closes and the furnace starts another ignition cycle because the pressure switch closed after that 1 2 second glitch. A draft inducer motor and pressure switch work together to make sure toxic gasses are vented from a furnace.

The source of pressure switch problems can sometimes be a pain to track down. A pressure switch is designed to sense the negative pressure created by the draft inducer motor during the furnace startup and to shut down the furnace ignition if the air pressure is inadequate. If the pressure switch is stuck it does not send enough power to the inducer and therefore the ignition sequence does not begin. Furnace diagnostics indicate pressure switch open with inducer on what could be the problem.

A furnace draft inducer motor vents toxic gases outside. A furnace pressure switch confirms the draft inducer motor is working. As noted above the pressure switches used for gas furnaces are almost always normally open. The pressure switch on a furnace may fail or get stuck in an open position and there are few simple checks you can complete before testing the switch.

If the inducer comes on the pressure switch is stuck closed. The furnace pressure switch sends a signal to the furnace control board that verifies the inducer motor is working. The furnace then runs awhile longer and this crazy cycle repeats pressure switch glitches open gas shuts off furnace starts another ignition cycle. This is not a repair.

Furnace nordyne model kg6rc 080c 16b used to work fine before but has not worked since reactivating gas. Tapping lightly on the pressure switch body may open the switch and the unit may start. Today i am focusing on the pressure switch used in gas furnaces that prove inducer fan operation. Only oem pressure.