Tempstar Low Pressure Switch for T4H560GKD300 — OEM 1177594 | Ships Today
OEM Guaranteed
Same-Day Ship
30-Day Returns
Secure Checkout
Overview
The OEM Tempstar Low Pressure Switch Assembly (part number 1177594) is a refrigerant-side safety control that protects the compressor on your T4H560GKD300 heat pump. It senses suction-line pressure and opens the 24V control circuit whenever pressure drops below a safe threshold — a condition caused by low charge, a refrigerant leak, restricted airflow, or a failing metering device. By interrupting the circuit, the switch prevents the compressor from running under a loss-of-charge condition that would otherwise lead to overheating and catastrophic failure. A faulty low pressure switch typically presents as a heat pump that won't start, short-cycles, locks out on a pressure fault, or runs only intermittently in cold weather.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1177594 |
| Type | Low Pressure Switch Assembly |
| Brand | Tempstar (ICP / Heil family) |
| Control Voltage | 24V |
| Function | Loss-of-charge / low-suction safety cutout |
| Reset | Automatic |
| Fitment | OEM direct replacement |
Compatibility
A direct OEM fit for the Tempstar T4H560GKD300 heat pump and related ICP / Heil / Comfortmaker systems that use switch assembly 1177594. Verify the existing part number and refrigerant fitting style before ordering.
Installation Guide
- Safety First — Disconnect power and verify zero voltage with a multimeter before touching any wiring.
- Access — Remove the outdoor unit service panel to expose the refrigerant lines and switch.
- Document — Photograph the wire connections and the switch's plumbing location.
- Remove — Recover or isolate refrigerant per EPA rules if the switch is brazed; for Schrader-mount assemblies, unthread the switch and disconnect the spade terminals.
- Install — Mount the new 1177594 switch, seal the connection, and reconnect the low-voltage leads per your photo.
- Test — Restore power, verify the circuit closes under normal pressure, and confirm the unit starts and runs without a pressure lockout.
Signs You Need a Replacement
- Heat pump won't start or locks out on a low-pressure fault
- Short-cycling that clears when the switch is jumped (diagnostic only)
- Intermittent operation in cold weather
- Visible corrosion or damage at the switch body or terminals
Shipping & Returns
Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.
Shipping Information
- Orders placed before 3PM CST ship same business day
- Standard delivery: 2-5 business days
- Express shipping available at checkout
- Free shipping on orders over $75
- Tracking number emailed upon shipment
Return Policy
- 30-day returns on unused parts in original packaging
- Electrical parts (capacitors, contactors, control boards) are final sale once installed
- Email info@nationalhvacparts.com to initiate a return
- Refunds processed within 5-7 business days