Furnace Pressure Switch Open Fault

The contacts in the switch are either stuck together or moisture has entered the switched and seized it in the closed position.

Furnace pressure switch open fault.

5 a slow draft inducer that might need a new capacitor or has slowed down. Normally this would indicate a failed pressure switch the furnace will test to make sure the switch is open before starting the ventor motor. 6 someone has sucked on the pressure switch with their mouth or forgot to unhook the pressure switch from the furnace before using a vac on the furnace. Connect the ohm meter to the pressure switch.

Put the door back on turned furnace switch on and still have 3 flashes saying pressure switch is stuck open. First turn the power of the furnace off. Furnace still did not come on. Next take off one of the power hoses and blow on it.

I replaced the pressure switch but still get the fault. When the system calls for heat and the inducer fan begins to run check each pressure switch terminal. I have a nordyne updraft furnace with a pressure switch open fault according to the troubleshooting chart. 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 is in the closed position the furnace stops the sequence and goes into lockout mode until the switch is open. Give it a few minutes. Use an ohmmeter to check if the pressure switch is opening or closing properly when heat is called for. On newer furnaces on a call for heat the ifc checks the pressure switch.

The switch will need to be replaced then you should make sure the vacuum. May be a time delay in your thermostat. Step 2 inspect the pressure switch. The hole where the pressure switch attaches to the draft inducer could be stopped up with water slug or dirty.

It is giving me a fault code of pressure switch stuck open. Pressure switches are used to stop the furnace from operating in an unsafe condition.