Just Had Inducer Motor and Pressure Switch Replaced Furnace Acting Up Again

Are you having trouble with your furnace'southward inducer fan?

Maybe it's just rattling a little bit. Or perchance it'south not starting up at all.

Either way, problems with a furnace inducer fan volition prevent your furnace from running– leaving your abode in the cold.

In this article, I'll cover ALL of the possible issues that your furnace's inducer fan tin experience. From bad bearings, no ability, and even what to do when information technology keeps turning on and off.

Let's become started!

Inducer fan is vibrating

If you hear a rattling or vibrating noise coming from your furnace'southward inducer, then it'due south usually non too much of a cause for alarm.

In well-nigh cases, the inducer fan housing is a little bit loose and it just needs to exist tightened back downward.

To set up a vibrating inducer fan, follow these steps:

1. Power downwardly your furnace. Turn off the power disconnect to your furnace then it won't turn on while y'all're taking it autonomously.
2. Remove the access panels to your furnace. Specifically, you need to remove the panel that gains yous access to the inducer fan associates.
3. Plow your furnace back on. Turn power back on to your furnace and set up your thermostat to heat way.
4. Await (and listen!) for the source of the vibrations. The thought is to watch your inducer fan turn on so y'all can identify what'south causing the vibrations. When working within your furnace, be careful since the inducer fan can get extremely hot, peculiarly if it'due south an 80% furnace. Here are a few tips:
   1. Printing on the inducer fan housing to see if that stops the rattling.
   2. Other times, it may be a spiral on the inducer fan assembly that needs to be tightened up.
   3. If neither of the in a higher place works, and then you can effort placing a shim between the inducer fan assembly and the furnace chiffonier to make the vibrations end. Use something metal such as a screw, nail, or sheet metallic. Do not use forest or plastic for a shim because those things can burn or melt.
   4. Debris inside of the inducer motor housing could likewise be the source of the vibration. I hash out debris inside the inducer below.
   5. The worst-case scenario is bad bearings in your inducer motor. I talk over bad inducer motor bearings below.
5. Fix the source of the vibration. Depending on the source of the vibration that you lot identified in the stride above, you may need to do something every bit elementary as tighten upwards a screw. Or something more complicated such as taking autonomously your inducer and cleaning its insides.
6. Put your furnace back together. Afterwards yous've removed the vibrations from the inducer, it'south time to reassemble your furnace. Put everything dorsum where it was, and close up its access panels.

Stuck inducer fan motor

A stuck inducer motor is another common inducer motor effect.

If your inducer motor is stuck, it is sometimes just a simple fix. Other times, you'll need to supersede the entire inducer motor assembly.

It just depends on what's causing the motor to exist stuck.

To fix a stuck inducer motor, follow these steps:

1. Power down your furnace. Turn off the power disconnect to your furnace and then it won't plow on while y'all're taking it autonomously.
2. Remove the admission panels to your furnace. Specifically, yous demand to remove the console that gains you access to the inducer fan associates.
3. Discover the inducer motor and give information technology a spin. Virtually inducers will have a piece on the dorsum of the motor that you can grip and turn by hand. Some inducers will have some fan blades recessed into the motor. For those, utilise a screwdriver to plough the fan blades.

   When spinning the inducer fan manually, there will be one of 3 outcomes:

   1. If the inducer motor turns freely, then at that place is probable an electrical power issue going on with your inducer motor. I cover inducer motor power testing below.
   2. If the inducer motor has a lot of resistance or if in that location is grinding when you endeavour to plough it, and so there is droppings in the inducer. Or the inducer motor's bearings are bad.
   3. If the inducer motor is stuck at showtime, but then spins freely, then it may have been just a temporary "binding" of the motor. This unremarkably happens during the first time you start up your furnace in the fall. The inducer motor can sometimes get a little stuck since it hasn't run for a few months.
4. Fix the stuck inducer motor. Depending on the crusade of the stuck inducer motor, you will need to ready it accordingly.

   I'll get over what you should exercise in each scenario below.

Debris inside inducer fan motor associates

Sometimes leaves or bird's nests can find their way down your exhaust vent and into your inducer fan housing.

If this is the case, and so you'll need to remove the droppings from the fan so information technology tin can spin freely once more.

The procedure for removing debris from your inducer fan depends on the type of inducer that yous take.

Some inducers are easy to accept apart and clean. For other inducers, the only option is a replacement.

Inducer fan motor bearings are bad

If your inducer motor is however grinding subsequently its fan is gratuitous of droppings, then its motor bearings are bad.

The bearings are responsible for keeping the inducer motor spinning smoothly every bit it rotates.

Unfortunately, motor bearings are not something that you lot can repair. And then you'll need to supercede the inducer fan assembly if the motor bearings are bad.

Inducer fan motor electric and power issues

If your inducer motor spins freely but won't plough on, and then it'southward likely an electrical or power upshot.

The outset thing that you need to check is if your inducer motor is getting ability from the furnace's control board.

Follow these steps to figure out if your inducer motor is getting power:

1. Use a multimeter on the voltage setting to test power going to the inducer motor. Probe the hot (black wire) and neutral (white wire). You should get 120VAC when furnace is in rut mode.
2. If you do not accept 120VAC going to the inducer motor, and then you demand to check the furnace's control lath:
   1. Check if the board is getting ability. Use your multimeter to examination for 120VAC going into the control board. The exact terminals that you lot need to probe will vary from furnace to furnace.

      One way to figure out which terminals to check is to look where the line side (white and black wires) of the transformer connect to the control lath. If your control lath is not getting 120VAC then you need to make sure that ability is on to your furnace and there are no tripped circuit breakers.

   2. Use your multimeter to test betwixt the R and C terminals on your control board. You should become 24VAC across these terminals. If yous don't measure 24VAC across the R and C terminals, so at that place is an issue with the command board or its transformer.
   3. Check if the board is receiving a call for heat. Use your multimeter to exam betwixt the W and C terminals on the control board. You lot should mensurate 24VAC across these terminals.

      If you aren't measuring 24VAC beyond the W and C terminals, and so in that location is an upshot with your thermostat since it is not calling for heat. You can always bypass the thermostat by using a wire to jump the W and C terminals to manually put your furnace into heating mode.

3. If you lot are measuring a low voltage to your inducer motor, such as 70 or 80VAC, then you need to check the wiring connections between the inducer motor and the command board. If all the wiring connections are good and you are still only getting low voltage going to the inducer motor, then it'south probable that the command board is bad.

Spring the R and W terminals on your furnace'southward control lath to bypass the thermostat

After you've checked that your inducer motor is getting ability and it's however not starting, it could exist something else.

Hither are a few different electrical problems that your inducer motor could have:

Bad inducer fan motor capacitor

The capacitor is responsible for providing the initial "push button" to become the motor spinning.

One of the telltale signs that your inducer motor has a bad capacitor is if the motor gets really hot without even starting. This means that ability is getting to the inducer motor, but the capacitor is not able to give it that initial jolt of electricity to get the motor started.

If the inducer fan motor capacitor is bad, then it volition need to be replaced.

Bad inducer fan motor motor windings

In some cases, extreme temperatures will cause the windings inside the inducer motor to burn out and go bad.

Sometimes, it will be obvious that the inducer motor is burned out. For instance, if you have the classic "burnt electric smell" coming from your inducer motor, chances are that the motor is burned out and needs to exist replaced.

To test if the inducer motor windings are bad, follow these steps:

1. Disconnect the inducer motor. Notice the wiring harness for the inducer motor and disconnect it. The inducer motor wiring harness is commonly white with 3 or 4 wires.
2. Use a multimeter to test the resistance across the inducer motor. Turn your multimeter on to the resistance or ohms (Ω) mode. Use the 2 multimeter probes to test the hot (ruddy or blackness wire) and neutral (white wire) pins on the connector that goes to the inducer motor. There should be betwixt 20-100 ohms of resistance between the hot and neutral wires, depending if the hot wire is for low or high speed.

   If your multimeter reads open line (OL) or a loftier resistance reading, and then your inducer motor windings are bad and the inducer motor assembly will need to be replaced.

The inducer fan motor connector is ordinarily white and has 3 or 4 wires

Bad furnace command board

If the inducer motor isn't getting power, then it could be an issue with the furnace control board. The control board is responsible for turning on and providing power to the inducer motor.

For more data on troubleshooting a furnace control lath, bank check out my article on furnace control boards.

Loose inducer fan motor wiring connectedness

If the inducer motor is only getting partial voltage (such equally 70 or 80VAC), then information technology could exist a loose connection.

Some other symptom of a loose wiring connection is an inducer fan that keeps turning on and off.

Check all the connectors between the inducer fan motor and the furnace control board to make sure they are tight.

Sometimes yous need to just unplug and then plug dorsum in the inducer motor to restore the connectedness.

Inducer fan motor won't stop running

If your inducer fan motor keeps on running all the time, it's near likely due to a tripped safety such as the high limit switch.

It could also be due to a bad command board that is "stuck" in the on position for running the inducer fan.

The first thing you demand to practise is turn off the power to the furnace and so the inducer fan stops running.

The inducer fan motor is not designed to be running 24/7– if it is, it may damage itself.

Next, you'll need to start troubleshooting to bank check what is causing the inducer fan motor to stay running:

• Check out my article on loftier limit switches hither.
• Bank check out my article on furnace control boards here.

Inducer fan motor keeps turning on and off

There are two common causes for an inducer fan that keeps turning on and off:

1. Loose wiring connection
2. Pressure switch issue

I already covered loose wiring connections above. Then I'll but become over force per unit area switch problems here.

Inducer fan pressure level switch bug

The pressure switch on an inducer fan is used to check that in that location is proper airflow out of the furnace's frazzle. Sufficient airflow is needed to exhaust all of the toxic combustion gases outside of your home.

The inducer'south pressure level switch needs to trigger before the furnace will ignite its burners and heat your home.

The most mutual cause of a pressure switch that's not triggering is blocked exhaust venting.

You can read my article on blocked furnace exhaust vents here.

The gist of the article is that you lot need to check for and clear out any droppings from your furnace's exhaust vent to ensure unobstructed airflow.

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Source: https://hvactrainingshop.com/furnace-inducer-troubleshooting/

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