How To Reset A Rheem Furnace

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Many homeowners choose Rheem furnaces to deliver consistent and reliable heating for their homes throughout the year. However, it's inevitable that you run into a few issues with your Rheem furnace. When this happens, one of the easiest ways to resolve it is by resetting the appliance. But how exactly do you do that? We've done the research to give you instructions on how to do this.

To reset your Rheem furnace, you will need to:

  1. Check to see if the pilot light is off.
  2. Set the thermostat to the lowest possible setting.
  3. Switch off the power.
  4. Close the gas supply to the furnace.
  5. Reignite the pilot light with a matchstick or lighter.
  6. Turn on the power and the gas supply.
  7. Press the reset button and hold for 30 seconds. 
  8. Raise the thermostat back up to your preferred setting. 

It's important to follow these steps correctly to perform your furnace reset safely and successfully. So keep reading, because we'll take a closer look at each step to guide you along. We'll also answer more of your related questions on this topic.

Technician servicing heating boiler, How To Reset A Rheem Furnace

8 Steps to Reset Your Rheem Furnace

fixing gas furnace

Knowing how to reset your Rheem furnace is vital. You'll have to reset your furnace if it has stopped working due to an electric power interruption. In addition, if your furnace is failing to heat evenly, not producing heat at all, overheating, or experiencing any other trouble, the simplest fix is usually a reset.

Here are the steps to successfully reset your Rheem furnace:

1. Check to see if the pilot light is off

You can find the pilot light near the bottom of your furnace. If it is turned on, turn the gas control setting to "off." See to it that the pilot light goes out.

2. Set the thermostat to the lowest possible setting

This step ensures your safety, as it prevents your furnace from coming back on while you're resetting it. Lowering the thermostat means it won't suddenly release hot air in case everything doesn't go according to plan.

3. Switch off the power

You will need to cut off the power supply to the furnace so you can avoid shocks and other hazards. To accomplish this, turn off the circuit breaker that controls your furnace.

4. Close the gas supply to the furnace

Along with cutting off the power supply, you will also need to turn off the main gas supply line. However, you'll need to keep the pilot gas supply line on. To do this, turn the gas knob to "pilot" and keep the knob in place.

5. Reignite the pilot light with a matchstick or lighter

Then, relight the pilot by lighting a match or using a lighter. Hold it to the small opening of the pilot flame jet. If your Rheem furnace model's light compartment is sealed, press the button for the piezoelectric spark ignition to start the pilot.

6. Turn on the power and the gas supply

Switch the power back on through the circuit breaker. After this, turn the main gas supply back on.

7. Press the reset button and hold for 30 seconds

The reset button is located inside the blower compartment - you can find it on the side of the blower motor. Remove the cover from the housing to access the button, then press and hold it for at least 30 seconds.

8. Raise the thermostat back up to your preferred setting

Complete the reset by setting your thermostat to the temperature of your choosing. With this, your furnace should function normally again. If this doesn't work or if your reset button keeps popping out, this means that there are more serious problems with your furnace. You'll need to consult with an HVAC repair professional right away.

Why is my Rheem furnace not heating?

Heating Central Gas Furnace Issue.

There are a whole host of reasons why your Rheem furnace isn't heating. Here are some of the most common issues that could cause this problem:

Unlit pilot light

Check to see if your pilot light is lit and relight it if it's not. If this doesn't work, you may need to replace your pilot thermocouple.

Take a look at this thermocouple on Amazon. 

Clogged air filter

A dirty air filter could prevent your Rheem furnace from properly heating your home. Luckily, this is easily solved: simply clean your air filter to restore proper airflow.

Issues with ductwork

If your Rheem furnace doesn't heat evenly and only heats certain parts of the home, your ductwork may be to blame. To check for this, go to each room in your house and put your hand on the vent. The ductwork there needs cleaning where little to no heating is produced.

You can also go to the attic in your home to see if there is unsealed ductwork or broken piping.

Issues with igniter

A cracked or faulty igniter will prevent your furnace from heating. To check for this, take out your igniter to see if it has cracks. If it doesn't, use your multimeter to test it for continuity. Whether it has cracks or does not have continuity, you'll need to replace your igniter.

Faulty flame sensor

A faulty flame sensor might not be able to detect that there is already a flame, which will cause the control board to keep the furnace from heating. A quick solution for this is to clean your flame sensor. If this doesn't work, you'll need to replace the sensor.

Take a look at this flame sensor replacement on Amazon.

Where is the flame sensor on a Rheem?

The flame sensor on a Rheem furnace is located at the back of the furnace. It's outside the burner assembly on the wall of the burner compartment. It should be in front of you once you remove the access panel.

How do you clean a Rheem flame sensor?

When dirty, a Rheem furnace's flame sensor will not be able to determine when there's a flame present which will cause the furnace to cease functioning. Cleaning your flame sensor will resolve this issue. Here are the steps to accomplish this task:

  1. Turn off electrical power to your furnace using the switch or through the circuit breaker.
  2. Remove the cover to access the flame sensor.
  3. Pull off the wire attached to the sensor.
  4. Remove the screws holding the sensor in place with a flathead screwdriver.
  5. Pull the sensor out from the bracket assembly.
  6. Clean the probe with emery cloth or fine steel wool that will rub off the carbon deposits.

How do I know if my furnace board is bad?

Closeup of heater circuit control board inside of furnace.

The furnace control board is at the heart of your furnace's operation. When it stops working, your furnace won't run either. A few telltale signs that your furnace control board is malfunctioning include:

  • Blinking LED warning lights located behind the access panel
  • Fluctuations in temperature when your thermostat is working properly
  • Interruptions in the normal event sequence of your furnace

You can perform a test to determine whether your furnace control board is faulty by following these steps:

  1. Check your manual to see how to access the LED light indicators and how to diagnose the issue using the error codes.
  2. Use a screwdriver to remove the access panels.
  3. Hold down the door switch with tape.
  4. Check to see if the control board indicator light is blinking to determine whether your control board is receiving electrical power.
  5. If you do not have a control board indicator light, find the common wire on your transformer. Then, use your voltmeter to perform a power test on your control board, transformer, and Molex plug.
  6. Test your terminal strip for power by touching your meter leads to the "R" and "C" wires.

How much does it cost to replace a furnace circuit board?

The average cost of a furnace circuit board replacement ranges from around $300 to $1,100. This will depend on the complexity of your furnace system.

In Closing

HVAC Installer Strips Small Wires for a new Residential Furnace

Resetting your Rheem furnace is an easy task that you can perform on your own successfully. Whether there's been a power outage or your furnace has suddenly stopped working, doing a reset can get it back up and running again.

However, if a reset doesn't work and your Rheem furnace still won't generate heat, you'll need to check for other issues that may be causing the problem. When in doubt, make sure to consult with an HVAC repair professional as soon as possible.

Enjoyed this article? Check out these other posts that we think you might like:

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