Troubleshooting a Furnace Stress Swap: Your DIY Information

For some cause, you’ve made it to this text that will help you troubleshoot your furnace strain swap.

Regardless of the cause, this text will show you how to perceive what a strain swap does, its function, the right way to verify that it’s failed, after which lastly, why it failed.

If you happen to’re additional down the street of understanding your drawback, simply skip to the part you want.

Bear in mind, although, your furnace strain swap is perhaps OK, and it’s simply tripping as a result of it’s doing its job, and studying by means of these sections totally might help you to determine if that’s the case.

🔥 What Does a Stress Swap Do?

furnace pressure switch on two stage furnace

A furnace strain swap is utilized in a furnace to substantiate that the draft inducer motor is successfully eradicating all the merchandise of combustion from the warmth exchanger.

It’s normally linked by tubing to the entry and exit of the warmth exchanger in order that it might see the distinction in strain that the inducer motor causes.

This strain distinction is set by the furnace producer.

🔥 The Function of Your Furnace’s Stress Swap

2 stage furnace dual pressure switch
2 stage furnace twin strain swap

The aim of a furnace strain swap is to sense a selected strain distinction when the inducer motor is operating.

The strain distinction might be affected by draft inducer motor failure, venting points, warmth exchanger points, and condensate drain points.

🔥 How one can Check a Furnace Stress Swap

A manometer reading the correct gas pressure of 3.5 inches water column

To check a furnace strain swap, you’ll need a manometer.

It’s an HVAC instrument that assessments strain variations by measuring inches of water column (“WC.).

You’ll want to connect the manometer to the tubing on the furnace strain swap to get a studying when the draft inducer motor is operating.

Upon getting that studying, you may evaluate it to the strain swap studying.

In case your studying is above the specification on the strain swap, then your swap has failed.

If the studying is under the specification, your strain swap is nice, and the issue is some place else.

If you happen to’re on this situation, you need to learn our article on furnace restore issues and options.

🔥 Kinds of Furnace Stress Switches

Gas furnace combustion chamber in action

🔧 Single-Stage Standard Furnace Stress Swap:

This strain swap has one tube from the swap to the physique of the draft inducer motor.

The 24-volt electrical connection on this swap closes and lets the electrical energy by means of as soon as the inducer begins and proves that the strain requirement is met.

🔧 Single-Stage Condensing Furnace Stress Swap:

This strain swap has two hoses, one going to the burner enclosure and the opposite to the condensate collector field.

That is completely different from a standard furnace as a result of this strain swap appears to be like for a distinction between the 2 pressures.

🔧 Two-Stage Condensing Furnace Stress Swap:

This works the identical manner because the above condensing furnace strain swap, besides there are two strain switches.

If there are two strain switches, they’re normally put in as a mixed half.

A modulating furnace might have three strain switches.

A substitute strain swap for a modulating furnace might be far more costly than the opposite choices.

🔥 How one can Troubleshoot a Furnace Stress Swap

furnace leak detection

Okay, so I’ve already described the right way to take a look at the strain swap to see if it failed or not, and now I’m going to explain how to determine what’s inflicting the nice strain swap to journey.

First, you’ll want to know the sequence of operations for the furnace heating cycle.

🔧 The Furnace Sequence of Occasions

Most furnaces undergo the under sequence of occasions to supply a house with heat air.

  1. The furnace management board will get energy.
  2. The thermostat sends a sign for the warmth to activate
  3. The inducer motor activates
  4. The strain swap proves the inducer is getting the right pressures
  5. The ignitor initiates
  6. The fuel valve energizes.
  7. The flame lights and enters the warmth exchanger
  8. The flame sensor proves that the furnace burners are lit.
  9. The blower motor activates and forces heat air by means of the ducts

With this text, we’re going to imagine that your furnace solely made it to step 4, and now we have to determine why the ignitor didn’t provoke.

If it did attempt to spark or glow orange, then your furnace drawback isn’t the strain swap.

🔥 5 Straightforward Issues That May Trigger Your Stress Swap to Journey

Every of the under examples occurs often and might be mounted by following the restore directions in our furnace restore article.

  1. A plugged port on the strain swap hose between the gathering chamber and the strain swap

A clogged hose port could possibly be attributable to particles or water.

You’ll be able to strive eradicating the strain swap hose and blowing it out to see if that solves the issue.

If it doesn’t, chances are you’ll want a brand new hose.

  1. A blockage in both the recent air consumption pipe or the flue pipe

We see this usually the place I’m from. It’ll both be snow, ice, a baby’s toy, or a critter that’s determined to nest within the pipe.

Clearing it may be tough, so chances are you’ll want to rent knowledgeable HVAC contractor to do that.

  1. A diaphragm within the strain swap that’s both ruptured or caught

In case your manometer has proven that your inducer is producing the right pressures, then your strain swap might have failed.

If so, chances are you’ll want a brand new strain swap.

If a brand new strain swap is required, it may be bought from most HVAC suppliers and adjusted out rapidly.

  1. A strain swap hose is kinked or broken.

That is fairly easy to identify and might occur when a strain swap tube rubs in opposition to the inducer motor cowl.

A strain swap hose may also be kinked when new elements are put in or throughout furnace upkeep.

  1. A strain swap hose has water in it due to a condensate drain concern

If the condensate drain will get plugged for any cause, water will again up and finally clog the strain swap hose.

If this occurs, you’ll have to unclog the drain to get it working correctly once more.

We now have a whole article on the right way to unclog a condensate drain that can show you how to out.

🔥 Putting in a Furnace Stress Swap

phyxter furnace repair

If the strain fails and you could substitute it, this can be very simple to do because it’s solely a few screws and a few wires.

Take some pictures earlier than you begin to make sure that the wires get put again on the appropriate strain swap terminals.

Additionally, ensure that to show the ability off earlier than beginning to substitute the strain swap or earlier than doing any furnace repairs.

🔥 Remaining Ideas on Troubleshooting a Furnace Stress Swap

Phyxter Approved Logo on Service Truck

It’s fairly uncommon to see a strain swap failure, so you need to undergo the 5 repairs listed above earlier than buying a manometer.

If you happen to can verify that the inducer fan is operating, the flue vent is evident, the condensate drain is evident, and there aren’t any damaged or kinked strain swap hoses, then it is perhaps value making that buy.

Do not forget that if modified improperly, each element in a fuel furnace can turn into a harmful concern.

So, should you’re uncomfortable altering the strain swap, you need to name knowledgeable HVAC contractor.

Wish to study extra about furnace restore? Take a look at our full furnace restore article right here.