Furnace High Pressure Switch Stuck Open

Replaced circuit board white rodgers 50a50 241 inducer motor comes on then get 3 fl read more.

Furnace high pressure switch stuck open.

Only oem pressure switches should be used. After all this the furnace should fire right back up. Or you test any voltage between 1 to 23 volts then you have bad contacts and the full power is not getting through causing the furnace to fail. The plunger may not be pulling in completely and may only bob around when the pressure builds up inside the furnace.

Spray silicon lubricant on the plunger and work it back and forth to loosen the part. Pressure switch stuck open replaced pressure switch still getting 3 flashes wich means pressure switch stuck open. The pressure switch works with a small plunger that pushes in and out. If the switch is open the inducer starts and the resulting pressure change closes the switch.

Furnace pressure switch troubleshooting. This is not a repair. If the inducer comes on the pressure switch is stuck closed. So go ahead and put the hose back on put the access panel back on the furnace turn up the thermostat to its highest setting.

Which is why i made this video that go. If the switch does not close after approx 1 minute the ifc goes into lockout mode. If your pressure switch is stuck it is most likely a problem in the running of the furnace. This might free the switch from sticking.

Inspect the pressure switch hose. Using a cloth and a wire brush remove any blockages and dirt from the secondary exchanger and the inducer. Turn off the power. If you have 24 volts the pressure switch is open and not proving the ventor motor.

Turn off the power to the furnace by switching off the disconnect switch located near the furnace. Pushing in the plunger closes the circuit to activate the blower motor so if the switch is stuck in the open position that means the motor will not run. When you do this you should hear a clicking noise. Check for obstructions in the hose.

On a few furnaces i have found the ventor motor seams to be running fine and power is good but fails on pressure switch. It doesn t take much pressure so don t blow too hard. If there is no disconnect. The pressure switch must be replaced.