Description
The Lennox 29M74 is an SPST differential limit switch. It is essentialto ensure that the Lennox HVAC equipment is operating safely, usually furnaces. The temperature inside the furnace is also monitored by the switch. It has a set point of 140°F and a differential of 30°F. This means that the switch will open when the temperature goes high, say 140°F. When the temperature drops by 30°F, the switch turns off and then on again to enable the furnace to work again. This auto shut-off keeps the furnace from burning too hot, a situation that might cause damage to the equipment or ignite fire.
