Testing Furnace Pressure Switch

Hook a manometer to the tubing and check the draft from the heat exchanger in inches w c.

Testing furnace pressure switch.

To test the pressure switch use a multi meter and measure the continuity of the switch as it opens and closes. Turn off the power. If you see anything clean it out. The switch wires have to be removed first.

Ensure the draft is above the required pressure. Turn off the power to the furnace by switching off the disconnect switch located near the furnace. The draft inducer should start. If there is no disconnect.

Check for obstructions in the hose. Set your meter to volts ac turn your furnace on so it is calling for heat. A multimeter will be needed to test the switch for continuity. Basically the switch needs to be tested to see if it is closing when the pressure diaphragm pulls in.

With a manometer or magnahelic. The steps are as follows. A multimeter is used to test the pressure switch and check the continuity of the switch whether it is closed or it is opened. The switch is being tested to check if it s closing when the diaphragm is pulled in.

Probe one lead of the pressure with one lead of your meter while touching the other lead of your meter to. How do you test the gas furnace pressure switch. To do this the pressure switch wires are removed and the furnace turned on.