High Limit Switch Furnace Troubleshooting

As a working example we examine the honeywell combination fan and limit control type l4064b.

High limit switch furnace troubleshooting.

The limit switch is a safety switch that monitors t. During your tune up not only will we inspect your limit switch but we will also take care of airflow issues with your system that can cause your limit switch to break down. When the temperature gets too high the high limit switch turns off the gas to the furnace. Clogged furnace filter a dirty or clogged filter blocks the air flow into the furnace which may raise the inside temperature of the unit.

In this episode of repair and replace vance shows how to replace the high limit switch in a gas furnace. A clogged air filter restricts airflow through the heat exchanger causing the furnace to overheat. Fan control limit switch. If the furnace failure code indicates an open limit or open high temperature switch or open rollout switch it is probable that the furnace has overheated.

One way to keep your limit switch in good shape is to schedule a furnace tune up every year with jerry kelly. Next check the filter. The flames would raise the temperature inside the unit and have no place to go getting hotter and hotter. Flip the switch on the side of your furnace and flip the breaker off and on again before you even think about replacing any parts.

This article describes in detail the testing and diagnosis of problems with warm air heating furnace combination controls also commonly called the fan limit switch on warm air heating systems. Limit switches turn off the burner and turn on the circulating fan if there is a high temperature condition in the furnace. As a safety the high limit switch turns the gas off when the temperature becomes too high. For example if the blower motor stopped running then no air would move through the unit.

High limit switch a high limit control switch will turn off the gas to a furnace if the temperature becomes too high.