Tempstar Low Pressure Switch for T4H330GKE100 — 24V Refrigerant Safety | Ships Today
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Overview
This genuine OEM low pressure switch assembly (part number 1177594) protects the Tempstar T4H330GKE100 heat pump from operating under loss-of-charge or low-suction-pressure conditions. Wired into the 24V control circuit, the switch opens when refrigerant pressure falls below its setpoint, shutting the compressor down before damage occurs from running low on charge. A failed or stuck switch can cause nuisance lockouts, a compressor that will not start, or — if shorted — loss of critical safety protection. Typical symptoms include a unit that short cycles, fails to start in cold weather, or repeatedly trips its control board fault.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1177594 |
| Type | Low Pressure Switch Assembly |
| Brand | Tempstar |
| Control Voltage | 24V |
| Function | Loss-of-charge / low suction protection |
| Fitment | OEM |
Compatibility
Designed for the Tempstar T4H330GKE100 heat pump condensing unit. This is the factory-specified low pressure safety control for this model. Verify the connection style (quick-connect vs. flare) and electrical terminals against your existing switch before installing.
Installation Guide
- Safety First — Disconnect power and verify zero voltage with a multimeter. Confirm system pressures are safe before opening the refrigerant circuit.
- Access — Remove the control/service panel to expose the switch and its wiring.
- Document — Photograph the wire connections before disconnecting.
- Remove — Disconnect the leads and remove the old switch from its port (recover refrigerant first if the port is not Schrader-type).
- Install — Mount the new switch, reconnect the 24V leads per your photo, and ensure the connection is leak-tight.
- Test — Restore power and verify the unit starts and runs without nuisance pressure trips.
Signs You Need a Replacement
- Compressor will not start or locks out on a pressure fault
- System short cycles or fails to run in low ambient conditions
- Switch reads open with normal system pressure
- Visible corrosion, damage, or a refrigerant leak at the switch port
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