Tempstar Low Pressure Switch Assembly for T4H436GKD100 — OEM 1177594 | Ships Today
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Overview
This is a genuine OEM Low Pressure Switch Assembly (part number 1177594) for the Tempstar T4H436GKD100 heat pump system. The low pressure switch is a refrigerant-side safety control that monitors suction-line pressure and opens the 24V control circuit if pressure drops below a safe threshold. This protects the compressor from running under a low-charge or loss-of-refrigerant condition, which would otherwise cause overheating and premature compressor failure. A failed or stuck-open low pressure switch will prevent the system from starting or cause intermittent lockouts, while a switch that fails closed removes the protection entirely.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1177594 |
| Type | Low Pressure Switch Assembly |
| Brand | Tempstar (ICP / Heil) |
| Control Voltage | 24V |
| Function | Refrigerant low-pressure cutout |
| Fit | OEM Direct Replacement |
Compatibility
Engineered as a direct-fit replacement for the Tempstar T4H436GKD100. This assembly is shared across many ICP-family heat pumps (Tempstar, Heil, Comfortmaker) of the same generation. Confirm your existing part number reads 1177594 before ordering.
Installation Guide
- Safety First — Disconnect power at the disconnect and verify zero voltage with a multimeter. Recover or pump down refrigerant if the switch is not equipped with a Schrader fitting.
- Access — Remove the condenser/control access panel.
- Document — Photograph all wire connections before disconnecting.
- Remove — Disconnect the two 24V control leads and unthread/unclip the switch from its refrigerant port; cap the line if open.
- Install — Mount the new switch on the Schrader/braze port, reconnect the control leads per your photo, and check for leaks.
- Test — Restore power and verify the system completes a cooling cycle without nuisance lockout.
Signs You Need a Replacement
- System will not start and the control board reports an open low-pressure circuit.
- Intermittent short-cycling or lockouts on cooling/heat-pump mode.
- Switch fails continuity test when refrigerant pressure is known to be normal.
- Visible corrosion, cracked housing, or damaged terminals.
Shipping & Returns
Ships same day on orders placed before 3 PM CST. 30-day returns on unused parts. 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