ICP Defrost Control Board for WPH4364000RKB1 — OEM Circuit Board | Ships Today
OEM Guaranteed
Same-Day Ship
30-Day Returns
Secure Checkout
Overview
This genuine OEM circuit / defrost control board (OEM part number 1178001) is the brain of the outdoor unit on the ICP / Tempstar / Heil WPH4364000RKB1 heat pump. It manages the defrost cycle, compressor and fan sequencing, reversing valve switching, and time/temperature defrost logic. When this board fails, the heat pump may stop defrosting (icing over in winter), fail to switch between heating and cooling, short-cycle, or stop running entirely. Installing the correct OEM board restores proper outdoor control and protects the compressor from icing and improper sequencing.
Specifications
| Spec | Value |
|---|---|
| OEM Part Number | 1178001 |
| Type | Defrost / Outdoor Control Board |
| Brand | ICP / Tempstar / Heil |
| Control Voltage | 24V |
| Function | Defrost timing, compressor & fan sequencing, reversing valve control |
Compatibility
Built as a direct factory replacement for the ICP / Tempstar / Heil WPH4364000RKB1 heat pump. It also fits related ICP-family heat pumps that shipped with this defrost control board. Verify the board's part number, connector layout, and terminal designations against your existing board before installing.
Installation Guide
- Safety First — Disconnect power at the disconnect and breaker, then verify zero voltage with a multimeter.
- Access — Remove the electrical/control access panel on the outdoor unit.
- Document — Photograph every connector, plug, and the defrost timer/jumper settings before disconnecting.
- Remove — Unplug the harnesses, release the board standoffs/screws, and lift out the old board.
- Install — Mount the new board, transfer the defrost timer/jumper setting, and reconnect every harness per your photo.
- Test — Restore power and confirm proper startup, defrost initiation, and heating/cooling changeover.
Signs You Need a Replacement
- Outdoor coil ices over and the unit never goes into defrost.
- Heat pump won't switch between heating and cooling modes.
- Compressor or fan short-cycles or won't start at all.
- No control voltage output to the contactor or reversing valve.
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