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Furnace Error Codes: Common Furnace Troubleshooting Codes and What They Mean

Experiencing issues with your furnace? Even the most reliable and top-of-the-line furnaces experience problems from time to time. Luckily, furnaces have built-in safety features and the ability to communicate error codes. These furnace error codes can help you, and your Edmonton furnace repair professional, uncover specific issues. This makes furnace repairs faster and more cost-effective.

There are many different furnace brands, each with slightly different error codes. However, the way a code is read, and the errors that are communicated, are typically very similar. So, let’s take a look at some of the most common troubleshooting codes and what they mean.

How do you read a furnace error code?
Trane Furnace Error Codes
Amana Furnace Error Codes
Lennox Furnace Error Codes
Ducane Furnace Troubleshooting Codes
Goodman Furnace Fault Codes

How do you read a furnace error code?

Although furnace error codes differ between brands, all the most popular furnace brands use a system of blinking lights to communicate error codes. To read a furnace error code, locate the LED light and note its blinking pattern. Be sure to count how many times the light flashes and to note how quickly it’s blinking. To determine what a particular light combination signifies, consult the installation guide for your particular furnace. 

To help you out, here are some of the most common error codes that Edmonton homeowners will come across.

Trane Furnace Error Codes

Trane products, including furnaces and air conditioners, are some of the most reliable on the market. However, that doesn’t mean they don’t have problems.

To help you determine what’s going wrong with your Trane furnace, let’s take a look at some of the most common error codes.

What does a red blinking light on a Trane furnace mean?

Like many other top furnace brands, Trane uses a red blinking light to communicate error codes. A red blinking light can mean different things. The meaning is determined by the number of times the red light blinks, as well as how fast it is blinking.

Here are some Trane furnace error codes you might encounter.

Trane Furnace Error CodeMeaningPotential Issue
Constant slow blinkingFurnace is functioning normally
Constant fast blinkingFurnace is functioning normally
Red light constant ONControl failureControl panel issue
Red light constant OFFCheck PowerPower off
2 blinksFlame failure (retries exceeded)Gas supply issue, flame rod not sensing flame, wiring issue, etc.
3 blinksPressure switch problemBlockage in vent, condensate drain plugged, etc.
4 blinksTemperature switch problem / Over temperature limitPlugged filter, plugged secondary heat exchanger, ductwork issue, etc.
5 blinksFlame sensed when no flame should be presentLeaky gas valve, stuck gas valve, defective flame sensor, etc.
6 blinks115 VAC power reversed polarity, poor groundingIssue with line voltage polarity or wiring, etc.
7 blinksGas valve circuit errorGas valve issue
8 blinksLow flame sense signalFlame sensor malfunction, low gas pressure, etc.
9 blinksCheck igniterCheck igniter

Need help fixing an issue with your Trane furnace? The plumbing and heating experts at ProSolutions PHAC can help. Give us a call at 780-453-6640.

Amana Furnace Error Codes

Amana HVAC systems are also highly-dependable and efficient. Similar to Trane furnaces, Amana furnaces use a blinking red light to signify an issue with the unit. 

Edmonton homeowners may come across these common Amana furnace error codes.

Amana Furnace Error CodeMeaningPotential Issue
Constant red lightNo signal from thermostatNo power, issue with connections
Constant flashingReversed polarityIssue with wiring or line voltage polarity
1 flashFlame failure / Lockout due to excessive ignition retriesGas supply interruption, flame rod not sensing flame, wiring issue, etc.
2 flashesDraft inducer not operating or pressure switch failure (closed pressure switch circuit)Draft inducer not working, short in the pressure switch, blockage in vent, condensate drain plugged, etc.
3 flashesOpen pressure switchPressure switch needs to be replaced, pressure switch hose improperly connected or blocked, loose wiring, etc.
4 flashesPressure error / High limit errorClogged air filter, drain tubes obstructed by debris or moisture, faulty wiring, etc.
5 flashesFlame sensed without call for heatValve closing too slowly, etc.
7 flashesFaulty flame sensorFlame sensor dirty or too far from flame, etc.

Don’t be left out in the cold! The Amana furnace technicians at ProSolutions PHAC will have your unit fixed in no time. Call us at 780-453-6640.

Lennox Furnace Error Codes

Have a Lennox furnace at home? The Edmonton heating services experts at ProSolutions are familiar with the Lennox brand – and we’re here to help. 

Here’s what you need to know if your Lennox furnace is on the fritz.

What does a blinking light on a Lennox furnace mean?

Like Trane and Amana, Lennox furnaces are equipped with LED lights that are used to communicate issues. However, unlike Trane and Amana furnaces, Lennox HVAC systems use red and green lights to convey error codes. These lights flash in specific patterns to signify a particular issue.

If the red and green lights on your Lennox furnace are blinking simultaneously (quickly or slowly), this means that the furnace is functioning normally. All other patterns signify an issue that may require furnace repair.

How do you read Lennox error codes?

Lennox error codes are read based on the colour of the light that is flashing and how fast the light is blinking.

Here are some common error code patterns that you might see, along with details about what they mean.

Lennox Furnace Error CodesMeaningPotential Issue
Red light – flashing quickly
Green light – flashing slowly
Reversed polarityIssue with electrical wiring
Red light – flashing slowly
Green light – flashing quickly
Low flame errorIssue with flame sense rod, dirty flame sensor, poor gas pressure, etc.
Red light – flashing slowly
Green light – solid
High limit switch openPlugged filter, dirty blower wheel, ductwork issue, etc.
Red light – off
Green light – flashing slowly
Draft inducer or pressure switch failureBlocked inlet or exhaust vent, cracked hose, draft inducer not working, short in power switch, etc.
Red light – on, on, off
Green light – on, off, on
Circuit board failureIssue with control panel or wiring
Red and green lights alternating, flashing slowlyFlame failureIssue with pilot light or ignition sensor
Red and green lights alternating, flashing quicklyIssue with voltageImproper main ground

Require assistance with your Lennox furnace? Our experts are here to help – 780-453-6640.

Ducane Furnace Troubleshooting Codes

Ducane furnaces are made by Lennox and are another popular choice among Edmonton homeowners. Like Lennox, Ducane furnaces use flashing LED lights (red and green) to communicate error codes. However, a green LED is only used to specify furnace error codes when there is a demand for high heat.

When facing an issue with your Ducane furnace, here are some furnace error codes you might run into.

Ducane Furnace Troubleshooting CodeMeaningPotential Issue
Light ONNormal operation
Light OFFNo powerPower off, issue with breaker, connections or fuse
1 flashFlame present with gas valve offDirty flame sensor rod, valve closing too slowly, etc.
2 flashesPressure switch error (pressure switch closed with inducer off)Issue with pressure switch, draft inducer not working, debris in the line, cracks in tubing, etc.
3 flashesLow fire pressure, rollout or limit switch openBlocked or cracked heat exchanger, blocked vent, low gas pressure, etc.
4 flashesHigh limit switch openPlugged filter, dirty blower wheel, etc.
6 flashesPressure switch cycle lockoutFaulty pressure switch, blocked vents or condensate drain pipe, etc.
7 flashesLockout due to no ignitionFaulty or dirty flame sensor, faulty igniter, dirty filter, etc.
8 flashesLockout due to too many flame dropoutsDirty flame sensor, flame sensor or igniter failure
9 flashesPolarity and phasing errorIssue with wiring
Green LED flashingHigh heat demand, high pressure switch openDirty filter, dirty blower wheel, etc.

For more help with Ducane furnace troubleshooting codes, give the experts at ProSolutions a call. 780-453-6640.

Goodman Furnace Fault Codes

Goodman furnaces come highly recommended by furnace specialists in Edmonton. The brand is well-built and reliable. But, as with any furnace, Goodman units can experience issues – especially since cold Alberta winters can take such a toll on these types of appliances.

If you run into problems with your Goodman unit, be sure to look for the fault code. Providing furnace error codes to your furnace repair specialist before they arrive will help them solve the issue faster.

Here are some common Goodman furnace fault codes you may come across.

Goodman Furnace Fault CodeMeaningPotential Issue
Light ONNo signal from thermostatThermostat not properly connected, issue with thermostat setting
Light OFFControl failureNo power, issue with connections
1 flashIgnition error (retries exceeded) / Flame failureFaulty or dirty flame sensor, faulty igniter, gas supply interruption, etc.
2 flashesPressure switch error (stuck closed)Short in the pressure switch circuit, faulty pressure switch, draft inducer not working, etc.
3 flashesPressure switch error (stuck open)
Blockage in pressure switch hose, pressure switch hose improperly connected, loose wiring, induced draft blower operating when it shouldn’t be, etc.
4 flashesOpen high limitDirty filters, wiring issue, blockage in flue, etc.
5 flashesFlame sensed with gas valve off (i.e. no call for heat)Leaky gas valve, gas valve stuck open, defective flame sensor, etc.
6 flashesOpen rollout switchBlocked or cracked heat exchanger, blocked vent, low gas pressure, etc.
7 flashesLow flame error
Low gas pressure, faulty flame sensor, dirty flame sensor, etc.
8 flashesIgnitor error
Faulty ignitor, ignitor not properly connected, wiring issues, etc.
9 flashesOpen pressure switch, induced draft blower onPressure switch hose cracked, blocked or improperly connected, faulty pressure switch, etc.
Continuous flashingReversed polarityIssue with wiring

Need Help with Your Furnace? Consult Our Edmonton Furnace Repair Experts

ProSolutions PHAC technician fixing furnace error codes

Many furnace problems will require the help of a trained professional – especially when it comes to electrical or gas issues. As well, in some cases, if an issue is not correctly solved it can be extremely dangerous. For example, if your heat exchanger is cracked. Therefore, if you aren’t a trained professional, it’s recommended that you consult a furnace repair expert to address furnace troubleshooting codes.

*Keep in mind, regular furnace maintenance and tune-ups can help minimize the need for repairs.


For all your furnace needs, ProSolutions is here to help. Feel free to consult our furnace repair experts at any time. And don’t forget to check out our furnace maintenance coupons for savings on our heating services.