Armstrong Furnace Repair Guide
Troubleshooting, Error Codes & More
(Updated for 2019)
A complete Armstrong furnace repair guide, from how to replace your air filter, to troubleshooting and error codes, model numbers and more!
Please note, the following is for informational purposes only. Any servicing you attempt is at your own risk.
Armstrong has been in the HVAC business for over 90 years, and they’ve always prided themselves on manufacturing quality furnaces that are highly efficient and dependable.
But, all furnaces need regular maintenance for peak performance, and even then problems can still arise. Because of this, it’s important to know what maintenance steps you should be taking to keep your furnace in good working order, and how to identify common problems so that you can fix them or call a certified technician if necessary.
How to Replace Your Armstrong Air Filter
The air filter in your furnace is one of the first lines of defence you have against poor air quality, but it can only do its job properly if it’s changed monthly during the heating season.
A clean furnace filter will make your furnace more efficient, reduce maintenance and repair costs in the future, and keep your indoor air clean and breathable. Changing the filter is simple. All you have to do is:
- Locate the access panel and remove it or slide it open
- Look near the cold air intake to find the filter
- Remove the old filter
- Align the new filter by following the arrows
- Slide in the new filter
- Close the access panel
What’s Wrong With Your Armstrong Furnace?
Remember to always turn your furnace completely off before opening it up to look around or attempt any fix.
|Is your furnace...||The problem might be your...||What's wrong?||How you can fix it:|
|Not heating?||Circuit Breaker/Fuse||Most likely, either the electrical system providing your furnace’s power has shorted or the power switch has blown.||Try resetting your furnace’s circuit breaker. If it has blown, you will need to replace it.|
|Igniter||The furnace’s igniter might either be cracked or faulty.||Check the part for cracks, if it is then replace the igniter. If it isn’t cracked, use a multimeter to test for continuity.|
|Cycling irregularly?||Thermostat||Your thermostat might be adjusting incorrectly, causing the furnace to cycle on and off too often.||If your thermostat has an adjustable calibration scale, adjust the heat anticipator. If this does not stabilize the unit, you may have to replace the thermostat.|
|Not blowing hot air?||Blower Motor||Your blower motor may have completely burnt out. If this doesn’t seem to be the case, then the connecting belt may have simply broken.||Test to see if power is reaching the motor. If it does, but isn’t running, the motor has likely failed. If the motor runs but air doesn’t move, the connecting belt has probably broken. You’ll have to replace the belt.|
|Blowing too much air?||Control Board||The control board regulates the amount of voltage that reaches each functioning part. If the relay that controls the blower motor has failed, it will continually send voltage to the motor.||Replace the control board.|
|Thermostat||The contact that controls the blower motor on your thermostat may be stuck closed, causing the blower motor to run continuously.||Use a multimeter to check for continuity. If it appears the thermostat is the issue, replace it.|
|Leaking water?||Drain Pipe|
|Starting and then stopping shortly after?||Flame Sensor||Your furnace’s flame sensor monitors the burner, detecting whether a flame is present. If it is either defective or dirty, it will not be able to detect a flame.||If dirty, clean the sensor using a fine abrasive pad. If faulty, replace the flame sensor.|
Armstrong Furnace Error Codes
Armstrong furnaces are equipped with an LED light on the exterior of the unit that can indicate how the furnace is functioning and whether there’s a problem. These error codes come as a series of flashes, and the number of flashes tells you what component is affected.
Here’s what those error codes mean:
|Armstrong Error Code||What this means|
|LED is on and not flashing||The furnace is operating normally|
|Single LED flash||Flame continues to burn when the gas is off|
|Two LED flashes||Problem with the pressure switch|
|Three LED flashes||Problem with the pressure switch|
|Four LED flashes||Problem with the high limit switch|
|Five LED flashes||Problem with the rollout switch|
|Six LED flashes||Problem with the pressure switch|
|Seven LED flashes||Problem with the ignitor|
|Eight LED flashes||The flame is dropping|
|Nine LED flashes||Problem with the voltage|
When Should You Call A Professional?
While you can troubleshoot a number of issues on your own, you may want to contact a trained furnace technician should you be experiencing certain issues with your Armstrong unit.
If after your troubleshooting your furnace still isn’t producing any heat, is leaking or dripping, or is making strange noises (gurgling, banging, whistling, etc.), there might be some broken internal mechanical or electrical components within your unit. In this case, you will want to contact a trained technician to service your Armstrong furnace.
Also, if you notice that your furnace is continuously switching itself off and on, you may want to call a technician. This may be a sign that something is not circulating properly within your furnace, possibly tripping up the sensors.
Who Should You Call?
Having a trusted HVAC contractor’s number handy is always a good idea, especially in winter when a broken furnace can be a large inconvenience. But HVAC technicians aren’t created equal, and choosing the right one could save you time, money, and headaches.
That’s where our independent HVAC contractor certification program can help because it will provide you with a list of trusted and certified companies that you can turn to for help when you need repairs and maintenance.
Armstrong’s Warranty Coverage
Armstrong furnaces all come with a 10-year parts warranty, as well as a lifetime warranty for the heat exchanger, as long as you register the furnace within 60 days of installation.
If your Armstrong furnace is unregistered, the parts warranty expires after five years, and the lifetime heat exchanger warranty drops to 20 years.
Armstrong Model Numbers
Current Armstrong Models
Discontinued Armstrong Models
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