Furnace Pressure Switch Stuck Closed

The pressure switch must be replaced.

Furnace pressure switch stuck closed.

If you get a pressure switch code and the inducer will not come on remove one of the wires from the pressure switch. The plunger may not be pulling in completely and may only bob around when the pressure builds up inside the furnace. If the allowed vent feet are exceeded then you will have trouble with the pressure switch not staying closed. If it s truly stuck closed you need to replace the pressure switch.

Pressure switch fails closed normally this would indicate a failed pressure switch the furnace will test to make sure the switch is open before starting the ventor motor. Nordyne furnace error code. Tapping lightly on the pressure switch body may open the switch and the unit may start. Furnace pressure switch troubleshooting.

Using a cloth and a wire brush remove any blockages and dirt from the secondary exchanger and the inducer. It needs to be open until the draft inducer comes on. If is in the closed position the furnace stops the sequence and goes into lockout mode until the switch is open. The leakage based on location could be a failed gasket or even the drain line connection.

When it thows a stuck pressure switch error you should check the voltage drop across it or disconnect it and ohm out. The contacts in the switch are either stuck together or moisture has entered the switched and seized it in the closed position. The source of pressure switch problems can sometimes be a pain to track down. If you have exceeded the number of turns the furnace will not run right and the pressure switch will not work or stay closed.

Which is why i made this video that go. Pressure switch stuck closed. The 90 degree turns in the venting sometimes are calculated as 5 feet of piping.