ICP Control Board for WPH4484000RKA1 — Defrost Circuit Board | Ships Today
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Overview
This genuine OEM circuit board (part number 1178001) is the factory replacement control board for the ICP / Tempstar / Heil WPH4484000RKA1 heat pump. On a heat-pump condensing unit this board manages the defrost cycle, sequences the compressor and reversing valve, and coordinates the 24V control signals between the thermostat and the outdoor components. It monitors the defrost timer and coil temperature, switching the unit into and out of defrost so the outdoor coil sheds frost in heating mode. A failed control board causes erratic operation — no compressor, a unit stuck in defrost, ice buildup on the outdoor coil, or a complete no-heat condition. Installing a new board restores correct cycle timing and reliable heating and cooling.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1178001 |
| Type | Control / Defrost Circuit Board |
| Brand | ICP / Tempstar / Heil |
| Control Voltage | 24V |
| Function | Defrost timing, compressor & reversing valve sequencing |
| Fitment | OEM |
Compatibility
Built as the direct replacement for the ICP WPH4484000RKA1 heat pump condensing unit. Because ICP manufactures for multiple brands, this board also services equivalent Tempstar, Heil, Comfortmaker, and Arcoaire outdoor units originally equipped with part 1178001. Match the board's part number and connector layout to your existing board before installing.
Installation Guide
- Safety First — Disconnect power at the disconnect and breaker, then verify zero voltage with a multimeter before handling the board.
- Access — Remove the service panel to expose the control compartment.
- Document — Photograph every plug and wire on the old board; note the defrost timer setting (jumper or dip switch).
- Remove — Unplug each connector, release the board standoffs or screws, and lift the board out.
- Install — Seat the new board, set the defrost timing to match the original, and reconnect every plug per your photo.
- Test — Restore power, run a heating and cooling call, and confirm the compressor, reversing valve, and defrost cycle operate correctly.
Signs You Need a Replacement
- Heat pump won't start in heating or cooling despite a good thermostat signal.
- Outdoor coil ices over because the unit never enters defrost.
- Unit gets stuck in defrost or short-cycles the compressor.
- Visible scorch marks, burnt relays, or a cracked board.
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