Furnace High Pressure Switch Stuck Open

Take off the end so you can blow through it to the pressure switch.

Furnace high pressure switch stuck open.

Pressure switch stuck open replaced pressure switch still getting 3 flashes wich means pressure switch stuck open. It doesn t take much pressure so don t blow too hard. Tapping lightly on the pressure switch body may open the switch and the unit may start. If the switch does not close after approx 1 minute the ifc goes into lockout mode.

The pressure switch works with a small plunger that pushes in and out. If the inducer comes on the pressure switch is stuck closed. The source of pressure switch problems can sometimes be a pain to track down. If there is no disconnect.

Replaced circuit board white rodgers 50a50 241 inducer motor comes on then get 3 fl read more. After all this the furnace should fire right back up. 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.

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 pressure switch must be replaced. 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.

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. Which is why i made this video that go. Turn off the power. Using a cloth and a wire brush remove any blockages and dirt from the secondary exchanger and the inducer.

When you do this you should hear a clicking noise. 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 you have 24 volts the pressure switch is open and not proving the ventor motor. This might free the switch from sticking.

Check for obstructions in the hose. Turn off the power to the furnace by switching off the disconnect switch located near the furnace. This is not a repair. Only oem pressure switches should be used.