Solved: Lennox iComfort Thermostat Error Codes 411, 225 and 31

 Swapping out a low-pressure shutoff switch can depend on the specific model of your outdoor unit. You could expect to pay between $200 to more than $600 depending on parts and air conditioning repair costs. The shutoff switch itself costs an average of $30 to $150.

Error code 225 is specific to your furnace, particularly the high-pressure switch. This switch is a safety component that releases excess pressure inside 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 perform as efficiently.

Seeing error code 31 on your thermostat means it hasn’t been able to communicate with your furnace for more than three minutes. Several components communicate with the thermostat, so you may find this error code when any of them malfunction or fail. Most of the time this can be traced back to an electrical problem, like old wiring or a loose connection.

A technician can take a look at all the connections and wiring of the communicating components of your furnace. They should test voltages and wiring ohms since particularly high resistance can result in a disconnection. With a special tool called a multimeter, technicians can narrow down where the disruption originated from. Sometimes this is the furnace’s float switch, a component that shuts down the furnace when the condensate drain pan is flooded.

With several possible causes, it may be difficult to estimate 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 may expect to spend anywhere from $200 to more than $800 for higher-range models.