How to Troubleshoot a Limit Switch Lockout on a Payne Gas Furnace

Payne gas furnaces use a primary burner system to create heat. These burners run on either natural gas or propane, which is ignited through an electrical ignition system. Because natural gas can present a combustion danger if it is not controlled precisely, Payne furnaces also come with limit switches designed to shut down the furnace if they detect problems with lighting the burner. This indicates issues with overall furnace operation and gas or airflow.

Lockout Process

Furnaces would not run well if they locked every time a burner failed to ignite. Instead, the Payne limit switch detects how many times a burner fails to turn on. The ignition cycle can run three times without the switch activating. After that, the limit switch will close off gas flow to the burner and force the system to enter a lockout mode, where units, including the air conditioner, will not function.

Response

Because of the danger involved in leaking natural gas and gas buildup, Payne does not want you to root around for the source of the problem yourself. If your furnace locks out, Payne suggests shutting down the furnace entirely, both power and gas lines. This reduces the chance of gas suddenly combusting in your burner while you wait for a repair. After the shut down, call a professional contractor with experience working with Payne furnaces to take a look at the system.

Airflow Problems

When a burner cannot light properly, the issue may be airflow. If no air is reaching the burner, it cannot combust and may enter lockout mode. This occurs most often because of a blocked or covered air vent. Snow and debris may be cutting off your furnace oxygen supply. Dirty air filters may also be responsible. Solve this issue by cleaning debris and replacing filters.

Other Possibilities

Gas valve and gas flow problems can also cause burner errors, which is why an experienced contractor needs to take a look at your system. It may also be a minor igniter issue, but contractors have the experience needed to look for gas issues or adjust igniters properly instead of only guessing at the problem. You may need to replace valves, burners or ignition systems to restore proper function.