When something’s messing with your HVAC system, one of the first places to check is your thermostat. Many models have a digital display that will display a specific numerical error code. This error code can be used to help determine the problem and streamline the troubleshooting and repair process for HVAC systems like your furnace.
This is even easier with smart thermostats like the Lennox iComfort model. Let’s review three serious error codes—411, 225 and 31—to learn what the problem is. We’ll also cover what steps your technician will take to fix the problem, and the possible costs to do so.
Solving Error Code 411
Error code 411 is an urgent priority to take care of. You’ll see this error code appear when the outdoor unit’s low-pressure switch malfunctions five times or more throughout one heating or cooling cycle. Since this error code involves the outdoor unit, it may be involved with your air conditioner. Each time the low-pressure switch opens incorrectly, the error count increases. Once it passes five strikes, the thermostat immediately switches down the outdoor unit. This is known as a lockout and is a safety feature designed to prevent damage.
Fixing the Problem
A technician will test the system charge using several methods, as the issue could be with the switch’s power connections rather than the low-pressure switch itself. Once the cause has been found, technicians can reset the outdoor unit by putting it in test mode or by resetting low-voltage power. Once the issue is resolved, the error code should automatically clear.
Estimated Repair Cost
Swapping out a low-pressure shutoff switch can depend on the specific model of your outdoor unit. You may expect to pay anywhere from $200 to more than $600 depending on parts and air conditioning repair costs. The shutoff switch itself costs an average of $30 to $150.
Clearing Error Code 225
Error code 225 is specific to your furnace, namely the high-pressure switch. This switch is a safety feature that releases high pressure within the furnace, such as when airflow is obstructed. When this error code appears, it means the pressure switch won’t close. Without steady airflow and pressure, the furnace won’t run as efficiently.
Fixing the Problem
The technician will watch the high-pressure switch to see how it functions. They’ll measure the pressure while it tries to close during a heating cycle as well as its general operating pressure. If they find a problem, an obstruction preventing airflow is the most likely culprit. There are a few places to look, such as the vent and combustion air inducer. Technicians will look at both these components as well as the condensate drain to find the blockage.
Estimated Repair Cost
Because there are a few places to inspect before an obstruction can be found, labor costs should be considered when fixing error code 225. Ultimately, the final cost of this furnace repair will depend on where the problem is found as well as how long it takes the technician to identify the source.
Lennox Thermostat iComfort Error Code 31
Seeing error code 31 on your thermostat means it hasn’t been able to communicate with your furnace for more than three minutes. Multiple components communicate with the thermostat, so you might find this error code when any of them malfunction or fail. Most of the time this can be traced back to an electrical issue, like old wiring or a loose connection.
Fixing the Problem
A technician can inspect all the connections and wiring of the communicating components of your furnace. They should test voltages and wiring ohms since especially high resistance can lead to a disconnection. With a special tool called a multimeter, technicians can find out where the disruption originated from. Sometimes this is the furnace’s float switch, a component that shuts off the furnace when the condensate drain pan is flooded.
Estimated Repair Cost
With several possible causes, it may be difficult to gauge the total repair costs of error code 31. Technicians will check the float switch to rule it out before systematically reviewing electrical wiring and connections. If the cause is damage or a failed component, replacement part costs should be included. You might expect to spend anywhere from $200 to more than $800 for higher-range models.
