How to replace a pressure switch in your gas furnace

When the cold weather hits, your gas furnace becomes a lifesaver, keeping your home cozy. But if it starts to act up, it can be frustrating. One common issue is a faulty furnace pressure switch. The good news is, replacing this switch yourself isn’t as difficult as it sounds. Let’s walk through the process of swapping out that faulty pressure switch and getting your furnace back in action.

Heads up: The tips we’re sharing might not match your furnace’s exact make or model. We do our best to dish out handy advice for all sorts of DIY fixes, but different models can have their own quirks—whether it’s troubleshooting steps, error codes, or replacement parts. For spot-on guidance, it’s a good idea to check your furnace’s manual or just reach out to us if you’ve got questions.

What is the pressure switch and why does it matter?

The pressure switch is a safety device that ensures your furnace’s venting system is working correctly. It monitors the air pressure in the system and prevents the furnace from running if there’s a blockage in the vent or an issue with the inducer motor. If it detects a problem, it shuts the furnace down to protect your home from dangerous gases, like carbon monoxide.

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Safety precautions   

Safety should always be a priority when working on any appliance. Here are a few practical tips to help you stay safe:

• Turn off the power to the appliance by unplugging it or switching off the circuit breaker before starting any maintenance or repairs. This protects you from the risk of electric shock.
• Wear insulated gloves to shield your hands from sharp edges, pinching hazards, or debris.
• Work at a steady pace and take your time to avoid accidents or injuries.
• Make sure your workspace is well-lit so you can clearly see and access the parts you’re working on.
• Keep the area clear of clutter, and ensure children and pets stay out of the workspace.
• Never handle internal parts with wet hands. Check that both your hands and the work area are completely dry.
• Refer to your appliance’s user manual for any specific instructions or safety guidelines related to the part or repair.
• Handle parts gently to avoid damage to the appliance or potential injuries from applying too much force.
• Use safety glasses when dealing with chemicals, dust, or large debris to protect your eyes from harm.
• If the appliance was recently used, give it enough time to cool down before working on any heated components.
• Take photos or notes of wiring connections and terminals before disconnecting anything to make reassembly easier.
• Avoid touching exposed wires or terminals. If you must handle wires, use non-conductive tools or wear insulated gloves to minimize the risk of electrical shock.

What you’ll need

• A screwdriver (Phillips or flat-head, depending on your furnace)
• A new pressure switch (make sure it’s compatible with your furnace)
• A digital camera or your phone (optional, for taking reference pictures)

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Get the right pressure switch

Make sure you grab a pressure switch that’s a perfect match for your furnace. Using the wrong part can cause all sorts of issues, even safety hazards. You can find the right switch by checking your furnace’s model number. If you’re not sure where to find that info, take a peek at our guide on how to find your appliance’s model number.

Steps to replace the furnace pressure switch

1. Locate the pressure switch. It is typically near the inducer motor, connected by a small rubber hose. If you’re having trouble finding it, refer to your furnace manual for more details or locate the model number for more precise instructions.
2. Carefully remove the wires connected to the pressure switch. If you’re unsure where each wire goes, snap a picture with your phone to reference later.
3. Gently pull the rubber hose off the switch. This hose connects to the inducer motor and is responsible for detecting pressure levels.
4. Remove the switch from its bracket. It is usually secured to the furnace with a small bracket.
5. If your new switch comes with its own bracket, you might need to replace it. Otherwise, you can reuse the existing bracket.
6. Use your screwdriver to remove any screws or clips holding the switch in place and lift the switch off the bracket.
7. Position the new pressure switch onto the bracket. If you’re using a new bracket, set it up first, then attach the switch to it.
8. Use the screws or clips you removed earlier to fasten the new switch in place. Make sure it’s tight and secure.
9. Connect the rubber hose to the new switch, ensuring it’s snug and there are no kinks or twists that could obstruct airflow.
10. Refer to the picture you took earlier and reconnect the wires to their correct terminals on the new pressure switch.
11. Turn the furnace’s power switch back to “On.” If you turned off the breaker, be sure to switch it back on.
12. Set your thermostat to a higher temperature and wait for the furnace to kick on. Listen for the usual startup sounds, like the inducer motor running and the burners igniting.

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Stay warm and safe with AppliancePartsPros.com

Thanks for reading! If you need replacement parts, grab your model number and head to AppliancePartsPros.com. We offer over two million parts and most orders arrive in two business days. If you need help finding the right part or placing an order, you can contact our team at 1 (877) 477-7278.

While you’re waiting for your new part to arrive, you can explore our DIY blog and watch thousands of video tutorials on our YouTube channel.

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