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Key Takeaways

  • Lennox furnaces are known for their dependability and efficiency, but like any complex equipment, they can experience issues. Common problems include the furnace not heating or blowing cold air, running continuously, short cycling, blowing too much air, water leakage, and noisy operation.
  • To troubleshoot, check the power supply, thermostat settings, air filter, and gas supply. Ensure the thermostat is set correctly, replace dirty filters, inspect for ductwork leaks, and clear any blockages in the condensate drain.
  • Familiarize yourself with error codes to identify issues such as pressure switch problems or gas valve malfunctions. If problems persist or involve complex components, calling a professional like Comfort Union is recommended to ensure safe and effective repairs.

Table of Content

Keeping a furnace in excellent condition isn’t always an easy task because of all the mechanical and electrical components. Despite Lennox Furnaces’ stellar reputation for dependability and efficiency, problems can arise with any complicated piece of equipment that is used in your home. In this article, we have listed some of the most typical issues with Lennox furnaces, along with detailed but easy instructions for fixing them.

Common Lennox Furnace Problems and Solutions

Understanding every Lennox Furnace Error Code

Here’s a concise breakdown of common Lennox furnace diagnostic codes and their meanings:

Red and Green Simultaneous Slow Flash

There was no call for heat, thus this is a sign of proper operating. At this point, the thermostat has not signaled for heat, so the furnace is running properly but isn’t actively heating the house. Unless the homeowner wants heat and the furnace won’t respond to the thermostat, they don’t have to do anything.

Red and Green Simultaneous Fast Flash

The presence of this error code indicates that the heating cycle is functioning normally. When this happens, it’s because the thermostat has sent a signal to turn on the furnace. The furnace is behaving as expected, so there’s no need to do anything, similar to the slow flash.

Red and Green Alternating Slow Flash

When a homeowner notices this pattern, it means the heater is waiting for instructions from the thermostat or control system. This is a typical condition when the furnace is turned on but not producing any heat. Except in the event that the furnace does not react to the request for heat, no urgent action is required.

Red and Green Alternating Fast Flash

This means that the furnace is in lockdown mode because of a malfunction. The system takes this precaution to ensure the furnace is safe from harm or hazardous operating conditions. A clogged vent or a dirty air filter are two typical problems that homeowners should inspect. It is recommended to seek the assistance of a professional expert if the problem persists after performing the basic inspections.

Either or Both Lights On, No Flash

In most cases, a more significant problem, like the device losing power or a faulty control board, is indicated by this code. Before troubleshooting further, homeowners should inspect the electrical panel for blown fuses or circuit breakers. If the power is not out, then a professional technician will need to have a look at the control board and maybe even replace it.

Red Slow Flash and Green Fast Flash

Pressure switches or inducer motor problems are common causes of this pattern. Any problems with the inducer motor’s operation or clogged vents should be immediately addressed by the homeowner. Because the problem can involve complicated component diagnostics and repairs, expert service is advised if unclogging the drains does not fix the problem.

Solid Red Slow Flash and Green On

The flashing of red and green at the same time is a common indicator of normal operation with a heat call. As long as it continues to provide heat, the furnace should not need any further attention.

Solid Red Slow Flash and Green Off

After a heating cycle, this code indicates that the system is entering cool-down mode. During this typical operating period, the furnace fan could keep turning to remove any remaining heat. Nothing needs to be done.

Solid Red Fast Flash and Green Slow Flash

There may be a problem with the gas valve or flame sensor if this happens. Maintenance on the gas valve, flame sensor, or both may be required. Gas components are complicated and sometimes dangerous, so it’s best to have a professional take a look.

Red On and Green Slow Flash & Red Off and Green Slow Flash

Depending on the context (whether it’s a call for heat or not), these codes indicate typical operation. They signify that the furnace is waiting for additional instructions or is currently heating up, respectively. Assuming the furnace is functioning normally, no further steps are needed.

Additional Troubleshooting Tips for Lennox Furnaces

It is often possible to avoid this trouble by calling a professional to fix your Lennox furnace by troubleshooting it yourself. Here are some specific things to look for and things to keep in mind as you try to figure out what’s wrong with your furnace.

When to Call a Professional

Even though you can fix most furnace problems on your own with some basic troubleshooting, there are times when it’s best to hire a professional. There is a high potential for injury or more damage when working with furnaces, particularly those that use gas or have complicated electrical components. In order to prevent further damage or risk to your home, it is essential to identify when an issue goes beyond basic homeowner troubleshooting.

Get in touch with an expert right once if you think there may be a gas leak. Do not attempt repairs on your own if you detect the odor of gas near your furnace; instead, evacuate the area and call emergency services or alert your gas provider.

If you try fixing the problem multiple times and it keeps happening, it may be a sign of a more serious issue that has to be diagnosed and fixed by a professional. Exceptions to this rule include issues with the heat exchanger or ignition of the furnace, as well as persistent error codes that persist after standard resets.

In order to diagnose and fix certain parts of the furnace, such as the control board, blower motor, or wiring, one needs technical knowledge and access to specific tools. Improper management of these components can cause more issues or perhaps the system to fail entirely.

The warranty on your furnace can be nullified if you try to fix it yourself. If you want to keep your warranty valid, most manufacturers will only let repairs be done by a trained technician.

Call Comfort Union for all your furnace problems

Comfort Union provides efficient and affordable HVAC services from trained professionals whenever you need them. We have a staff of highly skilled technicians who are committed to fixing your furnace quickly while maintaining the finest standards in the business. Hiring reliable experts like Comfort Union ensures that your furnace is handled with care and contributes to its continued efficiency and longevity.

Call us for more details on repairs, installations, and maintenance of your HVAC system like your heat pump, air conditioner, and furnace.

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