How To Clean A Furnace Pressure Switch? Vital Cleaning Tips

Understanding The Furnace Pressure Switch

To understand the furnace pressure switch with its parts, you need to know what it is and how it operates. The furnace pressure switch is a safety device that monitors the system’s pressure and controls the inducer fan’s operation. In this section, we will discuss two sub-sections: What is a Furnace Pressure Switch? and How Does a Furnace Pressure Switch Work? These sub-sections will provide you with a comprehensive insight into how the furnace pressure switch works and what it does.

How To Clean A Furnace Pressure Switch

What is a Furnace Pressure Switch?

A furnace pressure switch is a safety device in HVAC systems. It monitors the pressure inside the furnace to make sure it’s operating properly. It will shut off if the pressure increases or decreases too much.

The switch measures airflow. This could be caused by clogged filters or damaged ductwork. If there’s too much resistance, a fault code will appear. Heat won’t ignite until it’s resolved.

Some homeowners bypass the pressure switch when they have issues. However, this is not recommended. It compromises safety and could lead to serious damage. Why leave your safety to chance? Let the furnace pressure switch take care of it!

How Does a Furnace Pressure Switch Work?

A furnace pressure switch is key to HVAC systems. It checks air pressure and makes sure everything is ventilated properly. As the system starts up, the blower motor runs and sends air through the ductwork. The furnace pressure switch measures the pressure. If it’s too low or high, it shows an error and stops the system.

The switch has two types: open and closed circuits. If the circuit is closed, power can run to other parts of the HVAC equipment. If it’s open, no current passes and the power stops.

Furnace pressure switches are very sensitive to negative air pressure. If they’re not adjusted properly during installation or repairs, the readings will be wrong. This can cause system malfunctions.

To make sure the switch works, keep the vents clear of debris. Dirty filters can make the airflow slow and strain the system. Also, check the HVAC unit regularly. This can prevent problems like worn-out capacitors and fan belts. A dirty furnace pressure switch is like a traffic cop who’s fallen asleep on the job – nobody’s going anywhere fast.

Signs of a Dirty Furnace Pressure Switch

To recognize when your furnace pressure switch needs cleaning, start by focusing on identifying blockages in the flue pipe. This is the first thing that you should inspect when troubleshooting your furnace. Once you have ruled out the flue pipe as the cause of the problem, recognize the symptoms of furnace pressure switch failure, which may be indicated by a blinking light or error code on the control board. In this section, we will explore these sub-sections in detail to help you diagnose and resolve problems with your furnace pressure switch.

Identifying a Blockage in the Flue Pipe

It’s significant to find out if your furnace flue pipe is blocked. Here is a 3-step guide to assist with recognizing a blockage in the flue pipe:

  1. Look at the furnace pipe that comes out of your home’s roof.
  2. Are there any signs of debris or bird nests close to the pipe opening? These could be clear signs of a blockage. Obstructed air passages will make your furnace’s pressure switch off totally.
  3. If there isn’t any observable debris but low airflow from the vents, then perhaps there are clogs in your HVAC system.

It’s critical to understand that pressure switches are made to sense when something’s off and will stop working if things aren’t right. To get your furnace running well, and to make it last longer, you must do normal maintenance checks.

To put it simply, a clogged furnace flue pipe can create major issues with HVAC systems if not checked quickly. According to, “Blocked flue pipes can cause serious problems, such as carbon monoxide poisoning.” A malfunctioning furnace pressure switch is like peer pressure gone wrong.

Recognizing the Furnace Pressure Switch Failure

The furnace pressure switch is a must for your heating system. You risk problems like overheating, short cycling, and even gas leaks if you ignore it. Signs you need to clean it:

  • The furnace won’t turn on
  • rapid cycling
  • water damage near the switch
  • error codes on the display.

To keep your pressure switch in good shape, check the tubing for debris and moisture, replace or clean the air filter, and inspect the vent pipe. If you spot something off, call a technician ASAP. Even with regular maintenance, bad things can happen. I recall a case of a homeowner with a freezing furnace. On inspection, we found a clogged pressure switch due to years of debris. We cleaned it and saved him thousands in replacement costs.

Cleaning a furnace pressure switch is not for the faint-hearted. Be prepared to get your hands dirty!

Steps to Clean a Furnace Pressure Switch

To ensure good operation of your gas furnace, cleaning the furnace pressure switch is an essential step that you cannot ignore. In order to clean the furnace pressure switch with ease, we present you with a step-by-step guide to help you get the job done. The first thing you need to do is turn off the power to your furnace. Next, remove the pressure switch hose and clean it properly with the inducer motor and draft inducer. You also need to inspect the flue pipe and vent for any blockages before testing the furnace pressure switch.

Turning Off the Power to the Furnace

  1. Locate the circuit breaker or fuse box that controls your furnace. Turn it off.
  2. Check if the thermostat still works. If yes, repeat steps 1-3 to make sure all power is off.
  3. Find the main switch that connects the furnace to the outlet and turn it off too.
  4. Use a voltage tester to double-check if no electricity is running.

Remember, newer furnaces may need 240V of power. Check manufacturer instructions before you start cleaning.

Pro Tip: If you’re not sure, it’s best to get a professional electrician. Taking off the pressure switch hose can be messy, but it needs to be done.

Removing the Pressure Switch Hose

Unfastening the pressure switch hose is a must when cleaning your furnace. Skipping this step can lead to inaccurate readings and malfunctioning.

Here’s what you need to do:

  1. Step 1: Spot the Pressure Switch Hose
    Look for the pressure switch hose connected to your furnace. It’s usually attached to a fitting on the side or top of the switch.
  2. Step 2: Detach the Hose
    Use pliers to pull back on the hose clamp and slide it down over the end of the hose. Twist and tug on each side of the hose to loosen it. If needed, use a flathead screwdriver.
  3. Step 3: Check and Clean
    After removing, scan for any cracks or holes that might cause gas leaks or false readings. Clean with a brush soaked in soapy water to eliminate any dirt, debris, and grime.

Plus, always keep gloves on when dealing with these delicate parts.

Pro Tip: Snap a photo of your pressure hoses before taking them off. It’ll remind you how to reposition them when replacing them. Pamper your furnace by cleaning its pressure switch hose- just don’t expect it to ask for a massage!

Cleaning the Pressure Switch Hose with Inducer Motor and Draft Inducer

Keep your furnace pressure switch hose clean, especially when dealing with an inducer motor and draft inducer. Follow these steps:

  1. Turn off the furnace.
  2. Locate and disconnect the hose from both ends of the draft inducer and inducer motor.
  3. Clean with a small brush like a toothbrush, and check both ends of the hose.

Remember: Don’t use water or other liquids.

Also, inspect and maintain your furnace system. Clean the air filters and ensure proper ventilation.

By doing this, your pressure switch won’t fail, and your furnace will work all year!

Inspecting the Flue Pipe and Vent for Blockages

  1. Turn off the power supply before beginning the inspection.
  2. Carefully remove any coverings from the flue pipe and vent to access them.
  3. Inspect the pipe and vent for any dirt, dust, leaves, or nests.
  4. Remove any blockages with a brush with stiff bristles or a vacuum cleaner.
  5. Reinstall covers, making sure they are clean and free from debris.

Note: Animals might build nests in the flue pipe or vent, leading to restricted airflow and damage to your furnace.

Pro Tip: Check your furnace annually by scheduling professional service specialists for thorough maintenance. Test the furnace pressure switch – it’s simpler than testing your ex’s patience!

Testing the Furnace Pressure Switch

To replace your furnace pressure switch, it’s important to take a few steps. First, turn off the power and gas supply of your furnace. Then, disconnect the wires from the pressure switch terminals.

Next, use a multimeter to check for continuity across the two terminals of the switch. Also, make sure all tubing connected to the switch is clear of blockages or debris.

If any of these tests fail, you may need to replace the pressure switch. Remember to always refer to manufacturers’ instructions when servicing any parts of your furnace. Be sure to exercise caution and be properly trained before attempting any repairs.

Regular cleaning and maintenance are key for your furnace to work efficiently and safely. Don’t put off regular tune-ups! My neighbor recently learned this lesson the hard way when his furnace failed at 3 am in the middle of winter.

When to Replace a Furnace Pressure Switch

To know when to replace your furnace pressure switch, you need to look for certain signs which indicate a damaged diaphragm or hose. This is crucial, as a failed pressure switch can lead to costly repairs or even danger. In this section on ‘When to Replace a Furnace Pressure Switch’, you will discover information on the common causes of pressure switch failure along with the warning signs to look out for.

Signs of a Failed Furnace Diaphragm or Hose

Furnaces have a diaphragm or hose to regulate pressure. Signs of a failed one can cause issues from inefficiency to complete failure. Check for these signs:

  • Noise during operation
  • Inconsistent heat output
  • Cycling on and off
  • The trouble with the pilot light
  • Unusual smells from the furnace
  • No hot air

Replace your pressure switch if needed. Don’t wait, as issues can cost money. Also, maintenance is key to keeping your HVAC system in good shape. Regular inspections by experts can spot potential problems.

A homeowner had a broken diaphragm causing frequent switching between heating and cooling. No filter was present, so dirt was on the coils. Replacing the diaphragm and adding the correct filter fixed the issue.

Pressure switches can fail due to neglect, use, or bad luck.

Common Causes of Pressure Switch Failure

A furnace pressure switch is important for regulating the blower fan to heat efficiently. It can break due to dirt buildup, wiring problems, and mechanical failure.

Common Causes:

  • Clogged Air Filter: Stops airflow, increases system pressure, and can damage the switch.
  • Faulty Wiring: Poor connections or installation can cause voltage changes and damage.
  • Mechanical Issues: Problems with the fan or motor can affect the switch.
  • Condensate Overflow: Blocked drain line creates too much water and may damage the switch.

Maintaining your furnace is key. Mary almost lost two of her children on a freezing winter morning when their carbon monoxide detector went off. Luckily, they got help quickly.

Replacing a furnace pressure switch may seem hard, but with the right tools and effort, you’ll soon get some heat!


A furnace pressure switch is a must-have safety feature for your heating system. Cleaning it often avoids blockages, broken diaphragms, and starting failures. To clean it, identify and disconnect hoses, remove debris from the port, and check the diaphragm for damage. Use compressed air or vacuum to clear clogging in hoses and tubing. Then reconnect all components and test it with a meter before turning it on. Safety should come first when handling combustion gases.

If you’re not sure how to clean it, call a pro. They have the experience and tools for the job.

Neglecting issues with the pressure switch can lead to costly repairs later. This could include code violations, damage to the heat exchanger, control board, blower fan, and negative pressure inducer motor failure or draft inducer problem. Experts at said, “When your gas furnace tries but fails many times to ignite after you’ve cleaned the ignition sensor and flame sensor, you might have an IFC failure.