Goodman furnaces are some of the most reliable units in their price range. However, they still malfunction occasionally. When that happens, having an idea of the most common furnace problems and their causes can be extremely helpful.
The Goodman furnace problems you need to know are the failure to start, ignite, stay on, and heat. Other common furnace issues you need to be aware of are short cycling and strange noises.
Read on to learn more about the above furnace problems, how to detect them, and their potential fixes.
1. Goodman Furnace Won’t Start
For clarity, starting in this context doesn’t mean ignition. Your Goodman furnace may start and still fail to ignite, a different issue that we’ll tackle in the next section. This segment focuses on instances when your Goodman furnace won’t even start, which means the draft inducer motor will not turn on.
A Goodman furnace may fail to start due to the following reasons:
- No power supply or tripped circuit breaker and faulty wiring.
- Bad control board, transformer, capacitor, and draft inducer motor.
- Thermostat issues, including device defects and loose connections.
- Reverse polarity, albeit this issue may have persisted for a while.
How to Fix a Goodman Furnace That Won’t Start?
The appropriate fix will depend on what’s stopping your furnace from starting. Here are a few things to try:
Check the Circuit Breaker and Power Switch
If tripped, reset the circuit breaker, and replace it if it won’t reset. Exercise caution if you suspect a short in your house or the furnace. Inspect all the wiring on the furnace. Tighten loose connections and replace frayed or damaged wires.
Inspect The Thermostat
Next, inspect the thermostat to verify if it’s instructing the Goodman furnace to start. The most common thermostat issues are:
- Loose wires or connections
- Low power for the battery-run ones
- Irreparable device defects.
Change the batteries, tighten the connections, or replace the wires if necessary. If the thermostat has irreparable defects, replace it.
Test Electrical Components
Test the control board, transformer, and capacitor using a multimeter to find out if any of these parts have continuity issues or weaker terminal voltages. Ideally, you should get a certified HVAC technician to inspect these electrical parts, but you can replace them yourself if you have the required DIY skills and the tools for the job.
Should you choose the DIY route, you’ll want to check out the Youtube video below. It’s a handy reference that covers the intricacies of changing a Goodman furnace capacitor and control board:
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Inspect the Draft Inducer Motor
The draft inducer motor may have an electrical connection issue due to a bad control board or capacitor. It might also have a mechanical problem.
Check if the motor is hot to the touch. If so, chances are one of the internal components is burnt or broken. Replace the inducer motor if that’s the case.
Check for Reverse Polarity
Reverse polarity occurs if the neutral line is connected to the hot wire terminal and vice versa. A Goodman furnace will have a rapidly flashing light if there is reverse polarity. Refrain from starting the furnace until you fix this, and keep electrical conductors away from the furnace to avoid a shock.
Also, verify if the reverse polarity problem is limited to your Goodman furnace. Errors in rewiring or new electrical circuits in a house may create this problem. Some furnaces may run despite the reverse polarity, but the problem will pop up eventually, and the appliance will not operate.
2. Goodman Furnace Won’t Ignite
If this happens, verify that you have power and gas. Ensure the power switch and gas supply valve are on and then check if the draft inducer motor and blower fan are working.
If your Goodman furnace won’t ignite despite available power and gas, it may be due to the following reasons:
- Pressure switch issues
- Clogged hoses and nozzles
- Open or broken high limit switch
- Tripped or defective rollout switch
- Broken or sooty hot surface ignitor
How to Fix a Goodman Furnace That Won’t Ignite?
Goodman furnaces failing to ignite is one of the most common problems you need to know, but it is also among the easiest issues to resolve. All you need to do is use an elimination method to identify and fix it or replace the faulty part.
Let’s take a look at how to address each potential culprit.
The Pressure Switch
The pressure switch is usually open when your Goodman furnace is off, and it must close soon as the draft inducer motor starts. If this switch is broken, it’ll remain open or closed. Either way, the furnace won’t ignite.
You need to replace the pressure switch if it is broken. However, you might want to check the hoses and nozzles before you conclude that the pressure switch is the culprit. If the nozzles/hoses are clogged, unclog them and see if that solves your problem.
Here’s a Youtube video on how to unclog the pressure hose and nozzle:
The Hoses and Nozzles
Any blockage in the pressure hose or pipe will prevent the pressure switch from closing. If this happens, your furnace will not get the green light to initiate the ignition sequence. You need to ensure unobstructed airflow throughout the pressure hose so the switch can close for ignition.
If you suspect clogs in any hose, gently it out and blow through to clear clogs. Next, run a tiny wire through the nozzles to unclog them.
The High Limit Switch
The limit switch is a safety feature. Normally, it stays closed and opens when the furnace is too hot. When this switch is open, the furnace won’t ignite.
Luckily, all you need to do to find out whether the high limit switch is open is check the error codes on your furnace. Goodman furnaces typically have a light that flashes four times to imply that the high limit switch is open. If the switch is open, reset it and see if the furnace ignites.
The Rollout Switch
Like its high-limit counterpart above, the rollout switch is also for your safety. It’s meant to shut down the furnace when the flames spread beyond the burner chamber and heat exchanger.
Check the error codes to determine whether the rollout switch is what’s preventing your furnace from igniting. If you notice six flashes, this switch is open, and likely the culprit. You can reset this switch if it is tripped. If resetting doesn’t close it, you might have to install a new rollout switch.
Here’s a handy Youtube video on how to repair and replace the rollout switch:
The Hot Surface Ignitor
You can clean a sooty hot surface ignitor, but a cracked or broken one needs replacement. The hot surface ignitor will not work if the control board fails to provide the current required for the coil to heat up. To find out if this is the case, check whether the voltage at the hot surface ignitor’s terminals is sufficient.
3. Goodman Furnace Won’t Stay On
A Goodman furnace may fail to stay on due to the following reasons:
- Dirty or broken flame sensor
- Low or no gas supply
- Fluctuating or no power
- Thermostat problems
How to Fix a Goodman Furnace That Won’t Stay On?
The First thing you need to do is ensure the Goodman furnace has sufficient gas and power. Once that’s confirmed, proceed to investigate other potential causes.
Check the thermostat mode and settings to know if they are shutting the furnace and adjust them accordingly. Next, see if you have cracked or damaged the burner chamber or heat exchanger because that can trigger the rollout switch and stop the furnace.
Do not operate a Goodman furnace with a compromised heat exchanger and burner or combustion chamber. The same goes if the appliance has a tripping limit or rollout switch. Always contact a certified HVAC technician in such cases because they can pose safety hazards.
Last but not least, check the flame sensor and clean it with acetone if it’s dirty and sooty. Also, inspect its wiring and fix any dislodged, loose, or broken wires. If the flame sensor is broken, replace it because its failure to detect combustion will shut down the furnace.
Here’s a Youtube video on how to clean the flame sensor and replace the ignitor:
Read: Furnace Noise Problems
4. Goodman Furnace Not Heating
A Goodman furnace may fail to provide adequate heating due to:
- Low gas supply
- Poor airflow
- Blocked vents
- Clogged ducts
- Insufficient return
- Dirty air filters
- Failing motors
- Inefficient air handler
- Electrical problems
- Thermostat issues
How to Fix a Goodman Furnace That’s Not Heating?
Here are the troubleshooting steps for a Goodman furnace that’s not heating:
- Ensure adequate gas supply and airflow.
- Remove all obstructions from the supply and return vents.
- Check if the ducts are clean and dampers are open.
- Clean the air filters, including those on the return vents and at the furnace.
- Inspect the blower and draft inducer motor for overdue repairs or replacements.
- Check the fan for damage and clean the filter on the air handler.
- Review the thermostat mode, settings, and wiring to ensure they’re regulating the heating effectively.
- Inspect the voltages for the main furnace parts and replace the capacitor or board.
5. Goodman Furnace Short Cycles
An oversized furnace may short cycle if it heats your indoor spaces too quickly. Thermostat settings may also cause short cycling. High temperatures can compel a furnace to start soon after shutting because the indoor air doesn’t remain too hot for a long time when it’s freezing outside.
How to Fix a Goodman Furnace That Keeps Short Cycling?
Contact a certified technician to address short cycling. You can change the thermostat settings, but the short cycling problem may also be due to serious electrical and mechanical failures in the furnace. You may have a short in the control board or motor and other issues that require an expert to fix.
6. Goodman Furnace Makes Strange Noises
Mechanical noises, such as clicking, may be due to loose screws or broken parts inside your Goodman furnace. Electrical noises, such as humming or buzzing, are generally due to a loose component on the control board, wiring issues, and other failing parts of the circuit.
How to Fix Strange Noises in a Goodman Furnace?
Tighten the screws and lubricate the mechanical parts. Also, fix loose wiring on parts such as the transformer, capacitor, control board, and the rest of the furnace. Preventive maintenance of all the electromechanical components can make a Goodman furnace operate like a gentle breeze.
There you have it; six problems every Goodman furnace owner needs to be aware of and their potential fixes. Even if your unit doesn’t have any of these problems, it helps to have this kind of knowledge because you never know when breakdowns might strike. Hopefully, what we’ve covered today will help you act accordingly when your furnace starts misbehaving.