ducane furnace troubleshooting

Ducane Furnace Troubleshooting – Common Issues and Error Codes

One of the best parts of the market today is that it’s very generous. Finding reliable furnaces for a reasonable price isn’t an issue anymore; you only need the patience and time to decide on a model for your home.

Ducane furnaces make a reliable choice for many homeowners, and most of the gas models present a 95% AFUE rating. Even if high-efficiency models make a higher investment upfront, you will get your money back in time as the high-efficiency models lower the utility bills. Moreover, the high-efficiency models come with an adjustable speed blower, which runs quietly and ensures constant temperatures inside the house.

Bells and whistles aside, all furnaces will develop some problems at some point. They take intense use, running and stopping all the time. Even if issues occur, Ducane furnace troubleshooting codes will help you figure out the problem before the technician gets to you. Today, modern furnaces come with control panels with LED lights that flash, informing you of your furnace issue. Many of your furnace problems will be challenging to address; you will at least have an idea about what’s wrong with your furnace.

What are the most common problems with the Ducane furnaces?

Troubleshooting your Ducane furnace doesn’t have to be very difficult, especially if you’re meticulous about it. Here are the most common issues with your Ducane furnace:

Pilot light

When you’re trying to turn on your Ducane furnace and realize that the pilot light doesn’t light, you should check if the primary valve is switched to the “On” position. It’s also essential to examine the HSI (Hot surface ignitor); it could be damaged.

Don’t forget to see if something is clogging the pilot orifice or the control valve could malfunction. Check your Owner’s Manual for further investigation.


Should you realize that the burners don’t ignite, the first step is to see if the furnace is connected to the power supply. There should be no tripped circuit breaker, no blown a fuse, and no defective wiring either.

Sometimes, you will solve the problem only by replacing the fuse on the fan timer board or the transformer. When the gas doesn’t reach the primary burners, the primary valve could generate the problem. If it’s turned to the “On” position or if it’s opened, you have discovered to cause. Damaged wiring connections or loose wiring could also affect the proper operation of the furnace.

Replacing the whole valve system is a solution, but only the professionals have the knowledge and skills to do it.

Improper size of the furnace

A furnace that is too small for your household won’t be able to warm the house. But it can go the other way again, with a furnace that is too big for your home. In such a case, the temperature is reached too fast before the entire house is warmed up.

The gas input can also be too low for your furnace, so the unit cannot provide enough heat. Dirty filters that require cleaning and replacement can affect the heating abilities of the furnace. Clogged ductwork can press the blower speed to run fast, leading to overheating the furnace and malfunctioning.

What are the most common error codes for your Ducane furnace?

The error codes are useful, helping you decide what’s wrong with your furnace, but checking the error codes is just the first step to take when troubleshooting your Ducane furnace. You still have to start somewhere, so here are the codes that your furnace could be flashing.

Code-LED off

If that’s what you notice, there is no power to control, or the control hardware defect has occurred.

Code- LED on

Your furnace is operating correctly, so you have nothing to worry about.

Code- 1 Flash

When you notice 1 Flash on the control panel, the flame is present, whereas the gas valve is off.

Code_ 2 Flashes

If the pressure switch closed while the inducer was off, you would notice the Code 2 flashes.

Code- 3 Flashes

Ducane gas furnace three flashes code signals that rollout, aux limit switch are open or the fire pressure is low.

Code-4 flashes

Ducane furnace 4 LED blinking lights to inform that the high limit switch is open.

Code- 5 Flashes

It’s not used.

Code- 6 Flashes

The six flashes code informs that the pressure switch cycle is in a lockout.

Code-7 flashes

When there is no ignition, the lockout will occur, and the seven flashes code will inform you.

Code- 8 flashes

Should too many flame dropouts occur, the furnace will get in a lockout, and an eight flashes code will appear.

Code- 9 flashes

If the phasing and polarity are incorrect, the code nine flashes will inform you about the problem.

Here are the High- heat state-green LED codes:

Code- LED off

If you notice LED off, there’s no request for high heat.

Code- LED on

Your furnace has received the request for high heat, and it runs correctly.

Code- LED flashing

When the LED is flashing, it means that the thermostat sent the high heat request, but the high-pressure switch didn’t close.

What steps do you take before troubleshooting?

You will have to run some visual examinations before troubleshooting your furnace:

  • See if the furnace has power; the built-in ignition/blower control board should be on
  • The manual shutoff valves from the gas line to the furnace shouldn’t be closed.
  • Ensure that all wiring connections are safe
  • Please go over the sequence operation (it’s in the Owner’s manual).

Begin with setting the thermostat above the ambient temperature, paying attention to the furnace’s response. Be careful and check the proper system operation. For furnaces with built-in and self-diagnostic ability, troubleshooting is more straightforward. When something is wrong, a red LED’sror code will be displayed by the control board. The control never stops supervising its functioning and the system’s functioning. Should a failure develop, the LED will show an error code (go back to the codes).

Fault code history button

The control is capable of storing the last five error codes in memory. On the control, you should notice a pushbutton switch. If you press and release the pushbutton switch, the control will flash the previous error codes. The latest error code will be flashed first, whereas the control board will flash the oldest fault code last.

Should you need to delete the error code history, you have to press and hold the pushbutton switch for more than 5 seconds before releasing it.

High Heat State LED

For the A80UH2V and 80G2UH-V models, a green LED is found on the control board, indicating a high heat state.


The A80UH2V and 80G2UH-V models come with an adjustable speed motor and amber LED on the control board for displaying CFM. If you want to find out what CFM the engine generates at any moment, you will need to count the number of times the amber LED will flash. Every flash is for 100 CFM; you will have to calculate the flashes and multiply by 100 to identify the real CFM provided (10 flashes x100, will mean 1,000CFM).

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