Lennox 10U40 675-490# HIGH PRESSURE SWITCH 675-490# HIGH PRESSURE SWITCH

675-490# HIGH PRESSURE SWITCH

We carry a full line of Lennox high pressure switches including 675-490

The Lennox 10U40 675-490

Lennox 10U40 675-490

The Lennox 10U40 is a High Pressure Switch wired in accordance with NEMA GS1 Standards. The Lennox 10U40 is a high pressure switch for use with a gas fired furnace, air conditioner, or boiler system.

The Lennox 9U20, 10U20, and 10U40 Gas Furnaces are 2 stage models where the high pressure switch is designed to be adjusted to a lower temperature than the low pressure switch.

In a properly balanced system with no refrigerant leaks, the high pressure switch (HPS) will not cycle on and off. The HPS is designed to monitor the high side liquid line pressure. Once the low side gauge reaches the low side setpoint of approximately 15 psi, the HPS sends "high" to the controller, which then starts an energizing relay. This energizing relay is what activates a relay within the condensing unit that turns on the compressor. If there is a leak between the outdoor condenser and indoor coil (high side), it will cause cycling of the HPS as the liquid refrigerant

A combination control/pressure switch that controls compressor's starting function and it's pressure.