Tempstar Low Pressure Switch Assembly for T4H736GKD100 — 24V | Ships Today

Overview

This OEM low pressure switch assembly (part 1177594) is a safety control on the Tempstar T4H736GKD100. It monitors refrigerant suction pressure and opens the 24V control circuit if pressure drops too low — protecting the compressor from running on a low charge, a frozen coil, or a restriction. A failed or stuck switch will either nuisance-trip and prevent the compressor from starting, or fail to protect the system at all.

Specifications

Compatibility

Direct OEM replacement for the Tempstar T4H736GKD100 and equivalent ICP/Heil/Comfortmaker family units originally equipped with switch 1177594.

Installation Guide

1. Safety First — Disconnect power and verify zero voltage with a multimeter.
2. Access — Remove the condenser/heat-pump service panel.
3. Document — Photograph the switch leads and refrigerant port location.
4. Remove — Disconnect the 24V leads; if the switch threads onto a Schrader port, unthread it (minimal refrigerant loss). Brazed-in ports require refrigerant recovery first.
5. Install — Install the new switch onto the port (replace the seal/O-ring), reconnect the 24V leads per your photo.
6. Test — Restore power, confirm the compressor starts on a call, and verify the switch reads closed at normal operating pressure.

Signs You Need a Replacement

• Compressor won't start (switch stuck open / nuisance trip)
• Intermittent short-cycling on low-pressure lockout
• Switch fails to open on an actual low-charge condition
• No continuity change across the switch as pressure changes

Shipping & Returns

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