Gas Furnace Pressure Switch Troubleshooting

Also the fittings that the tubing fit into should be clear.

Gas furnace pressure switch troubleshooting.

Check the tubing from the inducer. A furnace pressure switch is a safety device located near the draft inducer motor of a gas forced air furnace. A pressure switch is designed to sense the negative pressure created by the draft inducer motor during the furnace startup and. It should be clear.

The switch activates with air force pushing a plunger in the mechanism which closes the circuit. The furnace then runs awhile longer and this crazy cycle repeats pressure switch glitches open gas shuts off furnace starts another ignition cycle. 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. When the pressure switch opens the gas valve closes and the furnace starts another ignition cycle because the pressure switch closed after that 1 2 second glitch.

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. The pressure switch has a pressure at which it closes which is typically negative. The switch is there to prevent the furnace from running unless the correct venting air pressure is present. Here is a quick breakdown of the steps involved in replacing a gas furnace pressure switch once you have sourced your new part.

If the pressure switch is stuck it does not send enough power to the inducer and therefore the ignition sequence does not begin. The pressure switch fitting may have a restrictor inside do not remove. The pressure switch on a lennox g16 gas furnace monitors whether the air blower is in operation. The pressure switch is an indicator of pressure problems in the furnace.

Ensure the draft is above the required pressure.