How To Test A Furnace Blower Motor With A Multimeter

June 26, 2024 Post a Comment

How to test a furnace blower motor with a multimeter

Turn off your vehicle, set your multimeter to Ohms, and check for resistance between the blower's positive and negative terminals. You may also turn the car key to run without starting the engine, put the cooling system at full blast, and check for DC voltage. If none of these produces a reading, the blower is bad.

How do you test a furnace blower motor?

How to Test a Furnace Blower Motor: Key Steps

Turn off the Power to the Furnace.
Take off the Furnace Access Panels. ...
Test the Continuity of the Motor Circuit. ...
Test the Thermostat. ...
Checking the Motor Windings. ...
Checking the Capacitor.

Should a blower motor have continuity?

The first step is to insure that there is continuity between the three terminals. Check black to white, black to red, and red to white. All should have continuity. Then check resistance.

How can I tell if my furnace blower motor is bad?

Here are some signs of a broken furnace blower motor:

Loud Operating Noises. When your blower has an issue, you might hear odd noises coming from your vents.
Weak or Absent Airflow. Weak airflow or total lack of it is the most obvious sign of a bad blower motor. ...
Overheating. ...
High Energy Bills.

What voltage should a blower motor be?

A blower motor should receive between 12 and 24 volts of power in order to operate properly. If the voltage is too low, the motor will not be able to start or run properly. Too much voltage can damage the motor.

How do you diagnose a blower motor problem?

If the blower motor isn't running you should:

Use voltmeter or ohmmeter to check for a blown fuse. If you find one, replace it.
Start car and see if blower motor works.
If the circuits are in good repair but the blower motor keeps blowing fuses, replace the blower motor [source: You Fix Cars].

What would cause a furnace blower not to kick on?

If the fan does not start, you have a wiring issue (circuit breaker trips) or motor problem (circuit breaker does not trip). While your thermostat may be at fault, only an HVAC technician can diagnose and remedy the issue correctly.

What tool do you use to test the load on a blower motor?

Most of us carry one of many electrical multimeters that are on the market to test electrical properties. On these meters, there is a selection for AC Amperage that allows for a wide range of testing sufficient for all sizes of residential blower motors. An electrical meter will range in cost from $60 to $500.

How do you know if your blower is bad?

Weak Airflow from the Vents This is usually the first indication that you may have a faulty blower motor. If the airflow coming out of the vents is weak, check the motor. It can mean that your furnace blower motor is having a hard time pushing enough air through the ducts to achieve your desired temperature.

How do I know if my blower motor needs to be replaced?

What Are Signs Your Blower Motor Needs to Be Replaced?

Poor or Airflow from Air Vents. This will be the first and most obvious sign your blower motor has a problem.
No Airflow At All From Vents. ...
Skyrocketing Energy Bills. ...
Strange Noises When You Turn on the Heat. ...
Overheating Blower / Weird Smells.

How do you know if a motor is bad on a multimeter?

Start by completely disconnecting the spindle motor from all power sources. Check each wire, including T1, T2, T3 and the ground wire. If the reading is infinite, your motor should be fine. If you get a zero reading or any continuity reading, you have either a motor problem or a cable problem.

How do I know if my blower motor capacitor is bad?

If the capacitor is bad, the blower motor may run slowly or inconsistently, or overheat easily. If you notice that your blower motor works strangely or short cycles, make sure to contact professionals to inspect your capacitor.

How do you reset a furnace blower motor?

How to Find and Reset your Furnace Motor Blower

Step 1: Turn off the power to the furnace.
Step 2: Remove the blower compartment cover. ...
Step 3: Make sure the blower is completely cooled off. ...
Step 4: Locate the reset button. ...
Step 5: Press the button in (assuming that this is your issue and that the button has popped).

How long should a furnace blower motor last?

How Long Does a Furnace Blower Motor Last? Blower motors are designed to last just as long as your furnace itself, anywhere from 10 to 20 years. Just as with any HVAC system, the better maintained and serviced your equipment is by experienced HVAC technicians the longer it will last and the fewer repairs you'll face.

How do I check the voltage on my HVAC blower motor?

And then you put one probe on there and one to the l2. Common neutral bar right here and you should

Is there a fuse for blower motor?

Many vehicles have two fuses for the blower motor, one in the interior fuse block and the other under the hood. The blower motor is usually under the dashboard on the passenger side.

Does a blower motor need a capacitor?

The fan or blower motor may not be able to start and blow air without the capacitor there to provide that “jump start,” so it provides a pretty vital function.

How do you test a blower motor resistance?

Together make sure we have continuity. So we're going to check between this terminal. And the

Can furnace run without blower?

The furnace can produce heat inside the combustion chamber—but that heat won't go anywhere if the blower fan isn't running. Because there's a danger of the furnace overheating without the blower fan, the furnace won't operate unless the blower has power.

Where is the reset button on my furnace blower?

It is usually located inside the blower compartment on the side of the blower motor. Be cautious as the housing may be hot. If the button is popped up, press it down.