Tempstar Defrost Control Board for T4H448GKC200 — 24V Heat Pump Control | Ships Today
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Overview
This is the OEM defrost control board (part number 1173636) for the Tempstar T4H448GKC200 heat pump. The defrost control board is the brain of the heat pump's defrost cycle — it monitors coil temperature and ambient conditions, then commands the unit into and out of defrost to clear frost and ice from the outdoor coil during heating operation. It also coordinates the reversing valve, compressor timing, and auxiliary heat staging. When this board fails, the heat pump may run continuously without defrosting, freeze the outdoor coil solid, short-cycle, fail to switch between heating and cooling, or stop responding to the thermostat entirely. This is a direct-fit 24V OEM replacement that restores correct, factory-spec defrost timing.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP / Heil) |
| Control Voltage | 24V |
| Fitment | OEM, model-specific |
| For Model | T4H448GKC200 |
Compatibility
Engineered for the Tempstar T4H448GKC200 heat pump and shared across ICP-family condensing units (Heil, Comfortmaker, Tempstar) that originally shipped with board 1173636. Always confirm the OEM number printed on your existing board before ordering.
Installation Guide
- Safety First — Disconnect power at the disconnect and breaker, then verify zero voltage at the board with a multimeter.
- Access — Remove the control-panel service cover on the outdoor unit.
- Document — Photograph every wire and connector position before disconnecting anything.
- Remove — Label and unplug the low-voltage harness and sensor leads, release the board standoffs, and lift out the old board.
- Install — Seat the new board on the standoffs and reconnect every lead exactly as photographed, including the defrost thermostat/sensor.
- Test — Restore power, run a heating cycle, and confirm the unit initiates and terminates defrost correctly.
Signs You Need a Replacement
- Outdoor coil ices over and never defrosts during heating
- Heat pump won't switch between heating and cooling modes
- Compressor short-cycles or runs continuously
- No 24V output to the reversing valve or contactor
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