Testing Furnace Pressure Switch

Set your meter to volts ac turn your furnace on so it is calling for heat.

Testing furnace pressure switch.

The switch wires have to be removed first. To do this the pressure switch wires are removed and the furnace turned on. There should be either two or three wires going into your pressure switch. Inspect the pressure switch hose.

How do you test the gas furnace pressure switch. Probe one lead of the pressure with one lead of your meter while touching the other lead of your meter to. With a manometer or magnahelic. Basically the switch needs to be tested to see if it is closing when the pressure diaphragm pulls in.

Check for obstructions in the hose. Ensure the draft is above the required pressure. A multimeter is used to test the pressure switch and check the continuity of the switch whether it is closed or it is opened. A multimeter will be needed to test the switch for continuity.

The pressure switch has a pressure at which it closes which is typically negative. The steps are as follows. The switch is being tested to check if it s closing when the diaphragm is pulled in. Hook a manometer to the tubing and check the draft from the heat exchanger in inches w c.

To test the pressure switch use a multi meter and measure the continuity of the switch as it opens and closes. If you see anything clean it out. Turn off the power to the furnace by switching off the disconnect switch located near the furnace.