Tempstar Low Pressure Switch Assembly for T4H342GKD100 — OEM 1177594 | Ships Today

Overview

This genuine OEM low pressure switch assembly (part #1177594) is a safety control on the Tempstar T4H342GKD100. It senses refrigerant suction pressure and opens the control circuit if pressure drops below the safe threshold — protecting the compressor from running on a low charge, a frozen coil, or a loss-of-refrigerant condition. When the switch fails or sticks open, the unit will lock out and refuse to start; when it sticks closed, the compressor loses its low-charge protection. Supplied as a complete assembly for a direct OEM replacement.

Specifications

Compatibility

Direct-fit replacement for the Tempstar T4H342GKD100 and ICP-family systems (Heil, Comfortmaker, Arcoaire) that use this low-pressure safety assembly. Confirm the cut-out/cut-in pressure rating and fitting type match your original before installing.

Installation Guide

1. Safety First — Disconnect power at the disconnect and breaker; verify zero voltage with a multimeter.
2. Access — Remove the electrical access panel and locate the switch on the suction line.
3. Document — Photograph the wiring and switch location before disconnecting.
4. Remove — Disconnect the leads; if the switch threads onto a Schrader-style port it can be changed without recovering charge, otherwise recover refrigerant first.
5. Install — Thread on the new switch (don't over-tighten), reconnect the leads per your photo, and check for leaks.
6. Test — Restore power, call for cooling, and confirm the unit starts and the safety holds the circuit closed at normal pressure.

Signs You Need a Replacement

• Unit locks out and won't start despite a proper charge.
• Compressor runs even when refrigerant is low (no protection).
• Intermittent nuisance trips on the low-pressure circuit.
• Visible damage or corrosion at the switch body or fitting.

Shipping & Returns

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