Teledyne Laars Cap Sensor/Pressure Switch with O-Ring, R0455400

The Teledyne Laars R0455400 is a cap sensor and pressure switch supplied with its O-ring. It is the genuine Teledyne Laars part, catalogued under Jandy Laars LXi heater parts.

What it does

A water pressure switch is the heater interlock that confirms flow through the heat exchanger before the burner is allowed to light. It is a safety device, not a convenience. A heater that fires without adequate flow will damage its exchanger fast, which is why a switch that has failed should be replaced rather than jumpered around.

Before you order

The available information lists this part under Jandy Laars LXi heater parts without naming specific models. Check R0455400 against the parts list for your heater to be sure it is the right switch. When you fit it, use the O-ring that comes in the box rather than the old one, since a compressed O-ring is a common source of a slow weep at the port.