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. 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. A multimeter is used to test the pressure switch and check the continuity of the switch whether it is closed or it is opened. With a manometer or magnahelic.

The switch is being tested to check if it s closing when the diaphragm is pulled in. If there is no disconnect. To do this the pressure switch wires are removed and the furnace turned on. If you see anything clean it out.

The steps are as follows. The pressure switch has a pressure at which it closes which is typically negative. Turn off the power. How do you test the gas furnace pressure switch.

Check for obstructions in the hose. To test the pressure switch use a multi meter and measure the continuity of the switch as it opens and closes. Basically the switch needs to be tested to see if it is closing when the pressure diaphragm pulls in. Set your meter to volts ac turn your furnace on so it is calling for heat.

Inspect the pressure switch hose. A multimeter will be needed to test the switch for continuity. There should be either two or three wires going into your pressure switch.