Carrier HH18HA270 Limit Switch For Crankcase Heater

The Carrier HH18HA270 crankcase heater limit switch is used in Carrier furnaces. This switch is approximately 24 inches long, 1.38 inches wide and 1.25 inches high. Its exact type whether sequencing or switching depends on the type of furnace in use. A sequencing switch may reduce power stages while a limit switch will completely deny power. In either case of the relay type, the switch also controls the temperature within the crankcase heater. When the temperature goes low below is a safe operation, the switch breaks the circuit and does not allow the power to flow to the heater again.