Troubleshooting a Furnace Stress Change: Your DIY Information

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

Regardless of the purpose, this text will make it easier to perceive what a strain swap does, its objective, how one can affirm that it’s failed, after which lastly, why it failed.

For those who’re additional down the street of understanding your drawback, simply skip to the part you want.

Keep in mind, although, your furnace strain swap could be OK, and it’s simply tripping as a result of it’s doing its job, and studying by way of these sections totally may help you to determine if that’s the case.

🔥 What Does a Stress Change 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 often linked by tubing to the entry and exit of the warmth exchanger in order that it may 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 Change

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

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

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

🔥 The best way to Check a Furnace Stress Change

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

To check a furnace strain swap, you will have a manometer.

It’s an HVAC device that exams 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.

After getting that studying, you possibly can 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 beneath the specification, your strain swap is nice, and the issue is elsewhere.

For those who’re on this state of affairs, it’s best 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 Change:

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 way of as soon as the inducer begins and proves that the strain requirement is met.

🔧 Single-Stage Condensing Furnace Stress Change:

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

That is totally different from a standard furnace as a result of this strain swap seems for a distinction between the 2 pressures.

🔧 Two-Stage Condensing Furnace Stress Change:

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 often put in as a mixed half.

A modulating furnace could have three strain switches.

A alternative strain swap for a modulating furnace will be rather more costly than the opposite choices.

🔥 The best way to Troubleshoot a Furnace Stress Change

furnace leak detection

Okay, so I’ve already described how one can check the strain swap to see if it failed or not, and now I’m going to explain how to determine what’s inflicting the great 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 beneath 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 proper pressures
  5. The ignitor initiates
  6. The gasoline 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 way 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 work out 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 Simple Issues That Might Trigger Your Stress Change to Journey

Every of the beneath examples occurs usually and will be fastened 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 may very well be attributable to particles or water.

You may attempt eradicating the strain swap hose and blowing it out to see if that solves the issue.

If it doesn’t, you might want a brand new hose.

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

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

Clearing it may be tough, so you might want to rent an expert 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 proper pressures, then your strain swap could have failed.

If that is so, you might 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 components 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 purpose, water will again up and ultimately clog the strain swap hose.

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

We now have an entire article on how one can unclog a condensate drain that may make it easier to out.

🔥 Putting in a Furnace Stress Change

phyxter furnace repair

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

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

Additionally, be sure that to show the facility off earlier than beginning to change the strain swap or earlier than doing any furnace repairs.

🔥 Closing Ideas on Troubleshooting a Furnace Stress Change

Phyxter Approved Logo on Service Truck

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

For those who can affirm 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 could be value making that buy.

Do not forget that if modified improperly, each part in a gasoline furnace can grow to be a harmful concern.

So, for those who’re uncomfortable altering the strain swap, it’s best to name an expert HVAC contractor.

Need to be taught extra about furnace restore? Take a look at our full furnace restore article right here.