Tempstar Low Pressure Switch for T4H348GKD100 — OEM 1177594 24V | Ships Today

Overview

This is the genuine OEM low pressure switch assembly (part number 1177594) for the Tempstar T4H348GKD100 heat pump. The low pressure switch is a refrigerant-side safety control that continuously monitors suction-line pressure. If pressure drops below the factory cut-out threshold — typically caused by a refrigerant leak, low charge, a blocked metering device, or loss of airflow across the indoor coil — the switch opens and interrupts the 24V control circuit to shut down the compressor. This protects the compressor from damaging low-charge and slugging conditions. A failed or sticking switch is a common cause of nuisance lockouts, a compressor that will not start, or short-cycling on the heat-pump system.

Specifications

Compatibility

Engineered as a direct-fit replacement for the Tempstar T4H348GKD100 heat pump. The same 1177594 assembly is shared across a range of ICP-built Tempstar, Heil, and Comfortmaker heat pumps of this series. Always confirm against your unit's parts breakdown before ordering.

Installation Guide

1. Safety First — Disconnect power at the disconnect and breaker, then verify zero voltage with a multimeter before touching any wiring.
2. Access — Remove the condensing unit service panel to expose the control area and refrigerant lines.
3. Document — Photograph the switch wiring and Schrader/quick-connect location before disconnecting.
4. Remove — Disconnect the 24V leads, then back off the switch from its refrigerant port (most low pressure switches use a self-sealing Schrader-style fitting, so no recovery is needed; confirm for your model).
5. Install — Thread the new 1177594 onto the port, snug it, and reconnect the 24V leads per your photo.
6. Test — Restore power, start the unit, and confirm the switch holds the circuit closed under normal operating pressure.

Signs You Need a Replacement

• Compressor will not start and the board reports a low-pressure lockout
• System short-cycles or trips on pressure during normal operation
• Switch fails to reset or shows an open circuit with correct refrigerant charge
• Visible corrosion, leakage, or physical damage at the switch body

Shipping & Returns

Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.