Furnace High Pressure Switch Stuck Open

Only oem pressure switches should be used.

Furnace high pressure switch stuck open.

If you have 24 volts the pressure switch is open and not proving the ventor motor. Check for obstructions in the hose. Turn off the power to the furnace by switching off the disconnect switch located near the furnace. When you do this you should hear a clicking noise.

If the switch is open the inducer starts and the resulting pressure change closes the switch. Inspect the pressure switch hose. It doesn t take much pressure so don t blow too hard. The source of pressure switch problems can sometimes be a pain to track down.

Pressure switch stuck open replaced pressure switch still getting 3 flashes wich means pressure switch stuck open. Turn off the power. Replaced circuit board white rodgers 50a50 241 inducer motor comes on then get 3 fl read more. If the switch does not close after approx 1 minute the ifc goes into lockout mode.

After all this the furnace should fire right back up. Which is why i made this video that go. Take off the end so you can blow through it to the pressure switch. Using a cloth and a wire brush remove any blockages and dirt from the secondary exchanger and the inducer.

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. This is not a repair. Spray silicon lubricant on the plunger and work it back and forth to loosen the part. On a few furnaces i have found the ventor motor seams to be running fine and power is good but fails on pressure switch.

If your pressure switch is stuck it is most likely a problem in the running of the furnace. 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. Furnace pressure switch troubleshooting.

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. The pressure switch must be replaced. If the inducer comes on the pressure switch is stuck closed. This might free the switch from sticking.