What to do When Your Furnace Pressure Switch Malfunctions

Furnace pressure switches are an integral part of your home’s heating system. If these devices are operating correctly, they will activate the burners when necessary and shut them off when not in use. This is to ensure that your furnace operates as efficiently as possible and uses only the minimum amount of fuel. If you have a malfunctioning pressure switch on your furnace, it could result in serious issues with your heating system. Your furnace may not switch on at all, or it could cut on and off repeatedly without stopping. The pressure switch must be checked and possibly replaced after every service call due to its sensitivity to dirt and moisture. Here are some things you should do if you discover that the pressure switch on your furnace has failed:

Check For Blockages

The most common cause of failure in a pressure switch is a blockage in the system. This can be caused by a buildup of dust, lint, and other debris inside the switch’s tube. If the tube is completely blocked, it will not be able to sense the pressure inside the system and will fail to operate. To determine if a blockage is a problem, start by shutting off the furnace and disconnecting the pressure switch. Next, use a long wire to remove any debris that may be clinging to the walls of the tube. Be careful not to bend the tube or do anything that could damage the pressure switch. If the blockage is cleared, you may be able to restore the pressure switch and continue to use it. If not, it’s time to move on to the next step.

Have the Furnace Pressure Switch Repaired

If the pressure switch is not completely blocked but is simply dirty, you may be able to have it repaired rather than replaced. This can be done by removing the switch from the furnace, cleaning it, and reinstalling it. While this solution is not ideal, it may be the best option for some homeowners. If the switch is broken beyond repair, a professional may be able to repair it using epoxy or other industrial adhesives. This is a more common fix for gas pressure switches since they are made of more delicate materials and more easily damaged by heat.

Have the Furnace Rebuilt

A furnace pressure switch is composed of several moving parts, including a spring and a bellows. If any of these parts become worn or broken, it may be possible to repair the switch or have it rebuilt. A rebuilt switch will be made from new parts and some may come with a warranty. Unfortunately, a pressure switch is a complex device. If any of the major parts are broken, it may not be possible to repair the switch. In this case, you may want to consider replacing the furnace since it will likely be more cost-effective in the long run.

Change the Furnace

If you have exhausted all other options and the pressure switch is completely broken, it may be time to scrap the furnace entirely. This is an extreme solution, but it may be necessary. If you choose to replace the furnace, you may also want to consider upgrading to a more efficient model. A new furnace will likely cost more than a pressure switch repair or rebuild, and it’s only a short-term solution. However, it will save you money in the long run. New furnaces are more energy-efficient and tend to last longer than older models.


A furnace pressure switch is an important part of your heating system. If you notice that yours is not operating correctly, it’s important to address the problem as soon as possible. You can check for blockages and clean out the system, or have the switch repaired or rebuilt if possible. If the problem is too extensive, you may have to replace the furnace entirely.