Furnace Pressure Switch Open Fault

A pressure switch is designed to sense the negative pressure created by the draft inducer motor during the furnace startup and to shut down the furnace ignition if the air pressure is inadequate.

Furnace pressure switch open fault.

The hole where the pressure switch attaches to the draft inducer could be stopped up with water slug or dirty. Now use the ohmmeter to check whether the pressure switch is functioning properly. When the system calls for heat and the inducer fan begins to run check each pressure switch terminal. Furnace still did not come on.

I replaced the pressure switch but still get the fault. First turn the power of the furnace off. Model xxxxx 072d 24b serial xxxxx nnn nnn nnnn switch xxxxx 632491 are there any dealers in northeast or southeast pa where i can buy these. Normally this would indicate a failed pressure switch the furnace will test to make sure the switch is open before starting the ventor motor.

Put the door back on turned furnace switch on and still have 3 flashes saying pressure switch is stuck open. May be a time delay in your thermostat. Use an ohmmeter to check if the pressure switch is opening or closing properly when heat is called for. 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. The contacts in the switch are either stuck together or moisture has entered the switched and seized it in the closed position. The switch will need to be replaced then you should make sure the vacuum. Give it a few minutes.

On newer furnaces on a call for heat the ifc checks the pressure switch. 5 a slow draft inducer that might need a new capacitor or has slowed down. Step 2 inspect the pressure switch. 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.

Next take off one of the power hoses and blow on it. It is giving me a fault code of pressure switch stuck open.