How do you test the gas furnace pressure switch.
Testing furnace pressure switch.
The draft inducer should start.
With a manometer or magnahelic.
If you see anything clean it out.
A multimeter is used to test the pressure switch and check the continuity of the switch whether it is closed or it is opened.
To do this the pressure switch wires are removed and the furnace turned on.
The switch is being tested to check if it s closing when the diaphragm is pulled in.
The steps are as follows.
Turn off the power.
Inspect the pressure switch hose.
The switch wires have to be removed first.
Basically the switch needs to be tested to see if it is closing when the pressure diaphragm pulls in.
The pressure switch has a pressure at which it closes which is typically negative.
A multimeter will be needed to test the switch for continuity.
Check for obstructions in the hose.
Hook a manometer to the tubing and check the draft from the heat exchanger in inches w c.
Probe one lead of the pressure with one lead of your meter while touching the other lead of your meter to.
If there is no disconnect.
There should be either two or three wires going into your pressure switch.
Set your meter to volts ac turn your furnace on so it is calling for heat.