Asked by: Higini Mrabet
home and garden indoor environmental quality

What does a relay do in a furnace?

Last Updated: 30th April, 2020

The electric relay in a furnace is responsible for relaying electrical power to the heating elements and the blower motor inside the furnace cabinet. The heating elements provide the heat to warm the air, and the blower motor sends this warmed air through the ductwork.

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People also ask, what are the signs of a bad blower motor relay?

Symptoms of a Bad or Failing Heater Blower Motor Resistor. Common signs include the car's heater not working or getting stuck on a certain speed, or something getting jammed in the blower motor.

Subsequently, question is, where is the blower motor fuse? Locate the fuse panel just beneath the dashboard on the driver side of the car. Remove the screw securing the fuse panel cover and remove the cover.

Then, how much does a relay switch cost for a furnace?

Relay switches cost $150 to $300 to replace.

What can cause a blower motor to stop working?

In a situation where the motor doesn't work on any speed, the most likely causes are: a blown power supply fuse, a bad motor ground connection, bad motor speed control module or a failed motor. On all systems, a failed blower motor is least likely. Start by checking the blower fuse and HVAC controller fuse.

Related Question Answers

Peter Taormina


How much is a blower motor relay?

The average cost for a blower motor relay replacement is between $74 and $85. Labor costs are estimated between $38 and $49 while parts are priced at $36.

Lizandra Choque


Where is the blower motor resistor?

It's located inside the dash, often on the opposite side of the steering wheel or inside the engine compartment on the firewall. A blower motor resistor or a blower motor control module is the part that controls the speed of the blower motor.

Tammara Hofschulz


What happens when blower motor relay goes bad?

Blown fuses
One of the first symptoms of a bad or failing AC blower motor relay is a blown AC blower motor relay circuit fuse. If the blower motor relay develops any sort of problem that hinders its ability to properly limit and distribute power, it may cause the blower motor fuse to blow.

Bujor Plieger


How do I know if it's my blower motor or resistor?

Usually a bad or failing blower motor resistor will produce a few symptoms that can alert the driver of a potential issue.
  1. Blower motor stuck on one speed.
  2. Blower motor does not work on certain settings.
  3. No air from the vehicle's vents.

Kautar Jeffery


How do you test a blower motor?

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

Wilkin Kirchstein


How much does it cost to replace a blower motor resistor?

The average cost for a blower motor resistor replacement is between $119 and $161. Labor costs are estimated between $47 and $60 while parts are priced between $72 and $101. Estimate does not include taxes and fees.

Serezade Lleras


How do I know if my limit switch is bad?

One common symptom of a malfunctioning limit switch is a blower fan that doesn't shut off. This happens when the switch simply fails to shut off the fan after the burners have stopped and the air exchanger is sufficiently cool. A bad switch also can prevent a furnace from operating at all.

Jene Grokholsky


How much does a furnace tune up cost?

Tune-up costs
Expect to spend anywhere from about $80 to $100 for a furnace tune-up, but more if repairs are also needed. Many companies offer service contracts or maintenance plans, which may reduce the cost of an annual visit from a pro and provide other benefits.

Yihan Servat


What causes furnace circuit board failure?

If the starting capacitor is failing, it can cause problems with your system. Replacing the capacitor is an inexpensive fix to solve the problem. A blower motor that is failing can also blow a fuse. It cause strain against the motor and draw too much power, which causes the system to short.

Kleber Dusinsk


How much does it cost to get your furnace cleaned?

If your inspection includes a furnace tune up, sometimes known as a furnace cleaning, that typically costs an average of about $60 to $85. "There are about 24 different things we do," Mills says. "We clean the heating system to improve efficiency and save money.

Argemiro Nodar


How do I clean my furnace?

How to Clean a Gas Furnace
  1. Turn off power/gas to the furnace. Turn off power to the furnace at the breaker box.
  2. Clean furnace surfaces. Wipe exterior surfaces with a damp rag.
  3. Remove the blower.
  4. Carefully clean the blower.
  5. Clean the pilot or hot surface igniter.
  6. Clean the flame sensor.
  7. Inspect the drive belt.
  8. Lubricate (but not too much).

Erondina Godos


Willia Juzefovich


How much does it cost to run a gas furnace for an hour?

The U.S. Department of Energy requires an AFUE of at least 90 percent for residential gas furnaces to receive an ENERGY STAR rating. This means an annual gas use of 660 therms at a cost of $660, or almost 31.7 cents an hour.

Hongfen Corpa


How much does it cost to replace a furnace flame sensor?

Depending on which furnace repair company you call, you can expect to pay anywhere from $350 to as much as $500 for a new flame sensor, plus the cost of the travel and diagnostic charge.

Eliria Maier


Why does the furnace fan stay on all the time?

When your thermostat is set to AUTO, your furnace fan should blow only when your furnace is in the middle of a heating cycle. But if your fan runs constantly, regardless of whether your furnace is heating, that's not normal. Your fan limit switch is on “manual override” There's a shorted thermostat wire.

Whitney Deitmer


Why does the thermostat not shut off?

Faulty thermostat. If your thermostat is not working correctly, the unit doesn't know to turn off even when the temperature is reached. If enough cool air escapes, the temperature in your space never reaches the set point and the system will keep running. Dirty or blocked condenser.

Jackie Siffredi


Can you bypass furnace limit switch?

First, turn the power off to the furnace. If you have an ohmmeter, you can measure the resistance across the switch. If the temperature is below the setpoint, the resistance across the switch should be zero. If you do not have an electrical meter, you can temporarily bypass the switch and see if the furnace works.

Anair Schurer


Why does my AC blower continues to run?

Other snafus such as a shorted thermostat wire can also cause the A/C or warm air furnace fan to run continuously. Those problems are explained at THERMOSTAT WON'T TURN OFF. 2. At the furnace or air conditioner air handler or blower unit: the fan limit switch may include a switch that manually keeps the fan running.

Nilva Fartaria


Why does my furnace fan not turn off?

If your furnace fan won't turn off, you most likely have one of these 3 problems: Your furnace fan limit switch is set to “manual override” The fan limit switch is faulty and needs to be replaced. There's a problem in your thermostat wiring.