In certain cases (after a power outage, for example), you would have to manually reset the furnace’s control board. Thankfully, practically anyone can do that.
Rebooting the furnace would also reset the control board. You would either have to push and hold the reset button for 10 seconds or restart the furnace at the circuit breaker – in the latter case, give the unit at least 10 minutes before turning it back on.
How to Reset Furnace Control Board?
In general, a control board does not have to be reset. But if you have noticed that there are no lights on the board, then you can try resetting the equipment – in a lot of cases, that might not help, as you are not fixing the root cause of the problem.
To reset the control board, you would have to reset the actual furnace. Simply turn the unit off with a switch or at the circuit breaker box and then turn it back on.
How Do You Know If Your Control Board Is Bad?
There are a few signs indicating that your furnace control board has gone bad:
- The LED lights on your furnace are showing ‘control board failure’ or ‘low voltage’
- The furnace is struggling to keep your house at a stable temperature – in case the thermostat is fine, the control board might be to blame
- If your furnace is short-cycling and you know that its elements are clean and the thermostat is operating correctly, then the chances are high that it’s the control board that has gone bad
What Causes Furnace Circuit Board Failure?
Here are the most common things that can cause furnace circuit board failure:
- Power surges – these unexpected spikes can easily damage the board’s transformer or blow a fuse
- Stuck relay switches – relays send power to the furnace’s components; at one point, they might become stuck because of dirt accumulation, misalignment, or loss of protective coating
- Loose wiring – a heating unit is a vibrating construction, and these vibrations can cause the wiring to go loose over the years
- Malfunctioning transistors – this is the part of the control board that usually fails the first; transistors can go bad because of age, static electricity, or power surges
- Normal degradation – over time, the control board will get damaged due to surges, vibrations, and thermal expansion
How Do I Test My Furnace Board?
- Locate the control board – you might find it under the front access panel, next to the blower.
- Inspect the control board – take note of any unusual smells or burn marks.
- Check the diagnostic light – it might be sending you an error code; if the light is off altogether, then the control board is not receiving any power.
- If the light is off, then test if the control board is receiving power or not.
- Jump the furnace terminals to make sure that the control board is the cause of the problem, not the thermostat or the furnace’s blower.
- Check if there is power coming out of the control board.
How Long Does a Furnace Control Board Last?
How long your furnace control board is going to last will depend on a lot of factors. On average, you can expect this component to serve you for 10-15 years.
How Long Does It Take to Change a Circuit Board?
It will take a professional anywhere between 2 and 5 hours to replace a circuit board. In some cases, it can take up to 8 hours.
How Much Does It Cost to Replace a Circuit Board on a Furnace?
The actual control board costs $50-$300, but you should be prepared to pay for the replacement labor as well. An HVAC contractor can charge you $250-$350 or even more, depending on how long the replacement is going to take.
Have a Question? Ask HVAC Technician
Click here to use the chatbox to speak with one of our technicians.
No in-home service calls. No appointments.
What Does Furnace Control Board Do?
A control board is sometimes called ‘the brain’ of the furnace. It controls and monitors each of the unit’s functions to ensure safe and effective operation.
The control board also assists in problem diagnostics as it features LED lights that can be used to send you an error code if something ever goes wrong in the furnace’s operation.
Where Is the Reset Button on Furnace?
Resetting the furnace would also restart the control board, in the majority of cases. If that’s what you want to do, then search for the reset button inside the blower compartment (on the side of the blower motor).
Do bear in mind, however, that not all furnaces have a designated reset button.
How Long Does It Take for a Furnace to Reset?
- If you are resetting the furnace with a reset button, then you should hold it for 10-30 seconds.
- If you’re rebooting the system at the circuit breaker, then make sure to leave the breaker off for at least 10 minutes before flipping it back to ‘on’.
It should take your furnace around 5 minutes to kick in after a reset and after you turn the thermostat on.
What Causes a Furnace to Need to Be Reset?
You might want to use the reset button if the unit is overheating and is about to trip the circuit breaker. Rebooting the system after a power outage might also be a good idea.
Furnace Reset Button Not Working
If you push the reset button, but it keeps tripping – there is something wrong in the system. The rest button will trip if:
- You run out of gas
- The gas valve is blocked
- The unit is overheating
- The flame sensor is dirty
- The air filter is clogged
Is It Safe to Reset Furnace?
It is safe to use the reset button once, but if it keeps tripping, you should not continue pushing it.
How to Reset Furnace After Power Outage?
Your furnace will most likely trip its reset button during a power outage. All you would have to do is push the button and hold it for a few seconds to reboot the heating unit.
Where Is Furnace Fuse Located?
The furnace fuse is typically located in the control box (close to the blower).
How Do I Know If My HVAC Fuse Is Blown?
You would have to replace a blown fuse before resetting the furnace. Locate the fuse, check its wires, and look for signs of cloudiness.
What Is a Hard Lockout?
You would have to manually reset a furnace if it goes into hard lockout. This will usually happen after the unit attempts to relight itself 3 times.
Why Is My Heat Not Kicking On?
The furnace will not kick on if there is an issue with the control board or the fuse is blown. However, the following issues are a bit more common:
- Problems with the thermostat
- No power
- An issue with the blower
- A dirty filter
- A malfunctioning gas valve
What to Check If Heat Is Not Working?
Check the thermostat first. Then you might want to make sure that all the power switches are on and that the air filter is clean.
How Do You Bypass the Thermostat on a Control Board?
Bypassing the thermostat on a control board can help you find out if your thermostat has gone bad or not.