Gas Furnace Pressure Switch Troubleshooting

The switch is there to prevent the furnace from running unless the correct venting air pressure is present.

Gas furnace pressure switch troubleshooting.

A gas furnace pressure switch closes to allow current to pass through and start the ignition of the furnace. A pressure switch is designed to sense the negative pressure created by the draft inducer motor during the furnace startup and. The furnace then runs awhile longer and this crazy cycle repeats pressure switch glitches open gas shuts off furnace starts another ignition cycle. It should be clear.

Other problems that could cause the pressure switch to not open are a dirty. The pressure switch is an indicator of pressure problems in the furnace. Ensure the draft is above the required pressure. If the pressure switch is stuck it does not send enough power to the inducer and therefore the ignition sequence does not begin.

Check the tubing from the inducer. Also the fittings that the tubing fit into should be clear. The pressure switch fitting may have a restrictor inside do not remove. By this point on an 80 efficiency furnace if you haven t found the culprit you will have to put on your best thinking cap because the issue could be any number of things including a bad board loose or bad.

Lennox pressure switches and carrier pressure switches are two popular furnace pressure switch brands but it is best to purchase based on your furnace model number. A furnace pressure switch is a safety device located near the draft inducer motor of a gas forced air furnace. The switch activates with air force pushing a plunger in the mechanism which closes the circuit. The pressure switch has a pressure at which it closes which is typically negative.

If your lennox does not activate normally during the ignition sequence try running a quick bypass of the pressure switch to determine if it is the.