How To Check Pressure Switch On Furnace? Quick Tips


Pressure switches for furnaces are essential for a safe and efficient heating system. They sense pressure levels and start the inducer motor, so the combustion sequence can start. Issues with pressure switches can cause problems with furnace performance or worse – carbon monoxide leaks! So, it’s important to check the switch regularly.

When troubleshooting, start by checking the pressure switch hose for any issues. Next, you can test the suction from the inducer motorturn on the furnace and feel the air coming out of the vent or flue pipe.

Testing your pressure switch with a multimeter is another option. Disconnect the power, remove the wires from the terminals, and set the meter to measure continuity. Blow into the ports on either side of the switch body – does it have continuity at rest? Now, check if introducing a diaphragm hole creates continuity.

Alpha Mechanical professionals suggest checking if anything between stages is damaged before repair. It’s also important to know that the furnace pressure switch forces a lockout if it senses negative pressure caused by something inside or outside until the room temperature reaches 140°F.

How To Check Pressure Switch On Furnace

Common Problems with Pressure Switches

To troubleshoot common problems with pressure switches in your furnace, the first step is to identify the issue. This can include pressure switch failure, inducer motor failure, or a damaged pressure switch hose. In the following subsections, we will offer insights and tips to help you diagnose and repair these issues to ensure that your HVAC system is working in good condition and keeps your home warm and safe.

Pressure Switch Failure

Pressure Switch Failure can cause big headaches for manufacturers. It can lead to costly downtime, safety issues, and damage to equipment. Worn-out electrical contacts and calibration errors from contamination or damage to sensors or moving parts are common problems.

This can cause abnormal system behavior like starting up or shutting down the machinery at the wrong time. Regularly inspect pressure switches for these issues. Proper maintenance should be done – like cleaning, adjusting calibration settings, and replacing worn-out parts.

Don’t let Pressure Switch Failure slow you down. Stay ahead by monitoring and taking action when needed. This can help avoid repairs and reduce downtime caused by defective machinery. Protect yourself from Pressure Switch Failure now!

Inducer Motor Failure

The inducer motor is part of a furnace’s combustion system. It evacuates gases through the flue. If it fails, this can be catastrophic – like gas leaks and bad air.

Maintain and clean regularly. Lifespan is usually 10-15 years. Listen out for weird noises and vibrations. Get a certified technician to replace it if it fails. Don’t do it yourself – may cause more problems.

Pro Tip: Regular maintenance is essential for avoiding inducer motor failure! If the pressure switch hose looks bad, switch to decaf!

Damaged Pressure Switch Hose

A damaged pressure switch hose is a common issue. It can happen due to several reasons like wear and tear, improper installation, or external damage. This can lead to inaccurate readings and system failures.

This can be a serious risk if not addressed. Regular checks and maintenance are necessary to avoid any problems. Replacing a damaged hose is easy and it’s best to get a professional to handle it.

Homeowners and businesses should be vigilant and check their equipment regularly. Neglecting this may lead to catastrophic consequences and financial losses. Prevention is always better than cure when it comes to pressure switches. Get your hoses checked for peace of mind.

Troubleshooting the Pressure Switch on the Furnace

To troubleshoot pressure switch problems on your furnace, start by checking for enough suction. Then, move on to checking the pressure switch body and port, followed by checking air pressure and switch terminals. Finally, you can test the pressure switch using a multimeter. These are the steps you need to take to determine if your pressure switch is in good condition or if it needs repair or replacement.

Checking for Enough Suction

When troubleshooting the pressure switch on a furnace, it’s essential to check for suction. This is key for the safe and efficient operation of the furnace. To check this, here are 3 steps to take:

  1. Turn off the power and disconnect the hose from the pressure switch.
  2. Cover the hose opening with your finger and turn on the power. If you feel suction, there’s enough. If not, look for obstructions in the air intake or exhaust vent.
  3. If no obstructions, try replacing the filter; a dirty one can restrict airflow and lead to low suction.

If there is still low suction after following those steps, it’s best to call a professional technician. They have access to special equipment and know-how to diagnose and fix issues.

Low suction can come from various sources, so it’s important to inspect all components before coming to any conclusions. warns, “A faulty pressure switch will often cause cycling issues in furnaces.” This highlights the importance of ensuring everything is functioning correctly in the system.

Check the pressure switch – look for any signs of life (or lack thereof).

Checking the Pressure Switch Body and Port

To make sure the furnace is running optimally, it’s essential to inspect the pressure switch body and port. Here’s a 6-Step Guide for doing so:

  1. Switch off the power. It’s important to turn off any power sources connected to the furnace before inspecting.
  2. Access the pressure switch. Locate it and carefully remove the cover to expose the switch body and port.
  3. Clean it. Check for corrosion or dirt accumulation that could affect functioning. Clean with a dry cloth or brush if necessary.
  4. Check for blockages. Inspect the port for blockages that could stop proper airflow and pressure readings. If no blockages, move to step 5.
  5. Use an air nozzle. Use an air nozzle to clean out the port in case of clogging. Be careful not to damage any delicate parts while cleaning. Install filters on your ducts to avoid future clogging.
  6. Reassemble and test. Put the furnace parts back together, turn on the power supply, and start the furnace system to check that it works properly.

It’s important to remember that this process should only be done by someone with experience and knowledge about furnaces. They’re critical to our daily needs, so care should be taken when removing or installing parts of the furnace system.

To ensure efficient operation, keep the furnace clean. Checking for corrosion and blockages is vital when troubleshooting components like the pressure switch body and port. Regular cleaning of these parts can extend their lifespan, improve energy savings via better pressure readings, and save you from having to call in a professional technician.

When it comes to the air pressure switch, remember to handle it with care – they’re the furnace’s delicate organs.

Checking Air Pressure and Switch Terminals

Troubleshoot your furnace like a pro – with a few simple steps!

  1. Turn off the power and remove the air switch cover.
  2. Measure the pressure in the tubes running from the switch to the combustion chamber. Use a manometer or pressure gauge to make sure it’s between 0.5-1.5 inches of water column (ICW).
  3. Next, use your voltmeter to check for voltage at the gas valve while running a new test cycle. Then use the meter to check across each switch terminal – make sure wires are firm and connections are secure.
  4. If all else fails, replace faulty parts.

Remember each furnace may have slight differences. Read the manufacturer’s instructions before troubleshooting. Also, note that irregular air pressure can cause multiple issues – not just switch malfunctions. So get maintenance checks done regularly and keep records of any recurring problems. Now you can rest easy knowing how to fix your furnace!

Testing the Pressure Switch with a Multimeter

Troubleshooting a furnace’s pressure switch requires testing it with a multimeter. Doing this will check if the switch works correctly, and rule out any other furnace issues. Here’s a handy 4-step guide:

  1. Turn off the power.
  2. Detach the wires from the terminals.
  3. Set the multimeter to measure resistance. Put each probe on one terminal, without touching anything else. This will show a closed circuit continuity. If it shows an open circuit, the pressure switch could be faulty.
  4. If you get an open circuit, try replacing the switch.

If this doesn’t help, contact an HVAC technician. Also, remember that the American Society of Heating, Refrigerating, and Air-Conditioning Engineers advises that a dirty filter can cause airflow problems. That can trigger the high limit safety control, making the equipment malfunction. So, keep your furnace in good shape!

Inspecting the Components Connected to the Pressure Switch

To inspect the components connected to the pressure switch in your gas furnace, check the draft inducer motor and flue pipe, examine the ventilation vents and collection chamber, and check the heat exchanger and gas furnace, is the solution to identify problems with the pressure switch. In this section, we will introduce you to these sub-sections briefly, allowing you to gain a better understanding of how to troubleshoot pressure switch failures and keep your home heating system in good working condition.

Checking the Draft Inducer Motor and Flue Pipe

To keep your furnace running smoothly, it’s important to inspect the draft inducer motor and flue pipe. Here’s what to do:

  1. Step 1: Check the motor is running smoothly and quietly. Tighten any loose bolts or connections.
  2. Step 2: Turn off the furnace to inspect the flue pipe safely. Look for corrosion, rust, or other damages.
  3. Step 3: Shine a light through one end of the flue pipe to detect blockages.
  4. Step 4: Reconnect any loose connections and bolts, then restore the furnace power.

It’s essential to regularly check these components. Otherwise, your furnace may not work properly. So, don’t forget to include them in your HVAC maintenance plan.

If you find any issues, an expert technician will be able to help. If left unchecked, the faulty faults could lead to carbon monoxide poisoning – which is fatal and undetectable without specialized equipment. So, always get help from the pros!

Examining the Ventilation Vents and Collection Chamber

Checking the ventilation vents and collection chamber is essential for the pressure switch to work properly.

These components control the air pressure required to activate the switch. The ventilation vents keep dust and debris away while letting air flow in. Meanwhile, the collection chamber collects any excess fluids and keeps them from interfering with the switch.

Make sure the vents are clear of blockages and damage. Clean or replace them with compressed air or special cleaning tools if needed. Don’t let the collection chamber overflow with fluid. Regularly check fluid levels and empty or replace them when necessary. Overflowing fluids may damage the switch’s internal parts.

Time to check the heat exchanger! Get ready for some serious heat!

Checking the Heat Exchanger and Gas Furnace

For efficient pressure switch functioning, heat exchanger and gas furnace inspection is key. Here’s the rundown:

  1. First, cut off the power to the furnace.
  2. Then, remove the access panels to see the inner parts.
  3. Check for any cracks or rust on the heat exchanger surface. A cracked heat exchanger can cause carbon monoxide to enter your home.
  4. Ensure all burners are clean and clear of dirt or debris. Use a brush or vacuum to take care of it.
  5. The blower motor must be cleaned of accumulated dust for proper airflow.

If there are major issues, get a pro to handle it. Safety first! To avoid bigger expenses, regular inspection by professionals is recommended. That’s how to switch up the pressure switch!

Tips and Insights for Checking the Pressure Switch on the Furnace

To troubleshoot pressure switch problems in your gas or furnace, follow these insights and tips for checking the pressure switch. You need to check for debris and damage in the pressure switch hose and use a flashlight to inspect the inside of the casing. If you’re unsure about handling it yourself, call an experienced technician for help. Lastly, test the pressure switch in different modes and stages to ensure it’s working in good condition.

Using a Flashlight to Check for Debris and Damage

To maintain your furnace’s pressure switch, debris, and damage must be checked. Use a flashlight to easily spot dirt or damage.

Here’s what you should do:

  1. Turn off the power supply. To avoid accidents, switch off the electrical supply from the furnace first.
  2. Identify the pressure switch. Check your manual for its location and then remove the cover.
  3. Shine the flashlight. Inspect the pressure switch’s nipple for debris, condensation, or corrosion.
  4. Check the wiring, hoses, and tubing. Look for dirt.
  5. Clean or replace, if needed. If anything needs cleaning/replacing, follow the furnace manual instructions.

Be gentle while cleaning. A broken part is harder to fix than one that’s just dirty.

If you don’t get your furnace serviced regularly, problems may arise. Our client experienced temperature inconsistency and high energy bills due to blockages in the pressure regulator sensing limit switches.

To prevent this, HVAC professionals recommend cleaning fittings around limit switches like hoses and tubing with a vacuum cleaner nozzle. If in doubt, call a pro, unless you want to risk playing ‘Fix the Furnace and Make a Bonfire’.

Calling a Professional Technician for Help

It’s wise to get pro help when things get complicated. Checking a Pressure Switch may seem simple, but can be dangerous for an untrained technician. Certified techs have the know-how and expertise needed to diagnose furnace troubles accurately. With their experience, they can pinpoint the root of the problem and provide long-term solutions.

On top of that, pro technicians offer assurance and security when they come to your doorstep. They use industry-standard tools and equipment, ensuring safe and efficient repairs or maintenance on your furnace system. Plus, they can spot issues that would go unnoticed.

When you call for help, provide accurate info about your furnace system specs and when you first spotted the issue. This helps them prepare for their visit or give helpful advice over the phone.

Angie’s List and HomeAdvisor report that most furnace repairs cost $150-$400, with emergency services being more expensive. So, hiring a certified technician can save you money on costly DIY mistakes.

Testing the Pressure Switch in Different Modes and Stages

Checking a furnace pressure switch is important. Here are tips and insights for testing it:

Test it in different modes and stages. Use a multimeter to check the resistance of contacts.

Ignition Trial (Gas Furnace)Closed
Run Mode (Gas or Heating)Closed
Blower Delay Off (Electric/Gas)Open

Check the wiring and tubing at the pressure switch and inducer motor. Refer to the manufacturer’s instructions when replacing.

Follow these tips and insights to ensure the pressure switch on your furnace is tested correctly. Like a doctor’s check-up, it’s uncomfortable but necessary for staying healthy and warm.


Troubleshoot the pressure switch on your furnace to check if it’s faulty or still good. Call an HVAC pro if you find any issues. This is important for safety and to stop damage. Check the hose from the inducer motor to the switch. Also, look at the flue or vent pipe; clear out any debris or damage that could affect suction. Make sure the draft inducer motor is working. Don’t forget to inspect the switch diaphragms. Check both sides for a hole and confirm they are in the casing properly. I had a gas furnace issue a few years ago. I couldn’t get it running. I attempted to replace parts but didn’t succeed. Then I called Alpha Mechanical. The technician found that the switch broke because of too much suction from the fan. He replaced both parts and the furnace worked again! Troubleshooting pressure switches isn’t easy. It’s best to leave it to experienced technicians. Inspect all parts and get help when needed so your unit functions properly and is safe.