Gas Furnace Pressure Switch Troubleshooting

A gas furnace pressure switch closes to allow current to pass through and start the ignition of the furnace.

Gas furnace pressure switch troubleshooting.

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 fitting may have a restrictor inside do not remove. A pressure switch is designed to sense the negative pressure created by the draft inducer motor during the furnace startup and. A furnace pressure switch is a safety device located near the draft inducer motor of a gas forced air furnace.

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

Check the tubing from the inducer. The pressure switch is an indicator of pressure problems in the furnace. The pressure switch on a lennox g16 gas furnace monitors whether the air blower is in operation. Here is a quick breakdown of the steps involved in replacing a gas furnace pressure switch once you have sourced your new part.

Ensure the draft is above the required pressure. The switch activates with air force pushing a plunger in the mechanism which closes the circuit. Other problems that could cause the pressure switch to not open are a dirty. If the pressure switch is stuck it does not send enough power to the inducer and therefore the ignition sequence does not begin.

The furnace then runs awhile longer and this crazy cycle repeats pressure switch glitches open gas shuts off furnace starts another ignition cycle.