Tempstar Defrost Control Board for T4H442GKB100 — OEM 1173636 | Ships Today
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Overview
This genuine OEM defrost control board (Tempstar part number 1173636) is the brain of the defrost cycle in your Tempstar T4H442GKB100 heat pump. In heating mode, frost builds on the outdoor coil; this board monitors coil temperature and run time, then reverses the system into a brief defrost cycle to melt that ice and restore efficient heating. It coordinates the reversing valve, outdoor fan, and compressor timing, and provides the 24V control logic that keeps the sequence safe and on-schedule. When this board fails, the heat pump either skips defrost (coil ices over and heating output collapses) or gets stuck defrosting, wasting energy and blowing cold air indoors.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP / Heil) |
| Control Voltage | 24 VAC |
| Application | Heat Pump Defrost Cycle Management |
| Fitment | OEM Replacement |
Compatibility
Direct OEM replacement for the Tempstar T4H442GKB100 heat pump. As the factory 1173636 board, it is also used across compatible ICP-family heat pumps (Tempstar, Heil, Comfortmaker, Arcoaire) that specify this defrost control. Match your existing board's part number and terminal layout before installing.
Installation Guide
- Safety First — Disconnect power at the outdoor disconnect and breaker, and verify zero voltage with a multimeter before touching the board.
- Access — Remove the control/electrical access panel on the condensing unit.
- Document — Photograph every wire and harness plug on the existing board before disconnecting.
- Remove — Unplug the harnesses, note the defrost timer/jumper pin settings, and unsnap or unscrew the old board from its standoffs.
- Install — Mount the new 1173636 board, set the defrost timing pins to match the original, and reconnect every harness per your photo.
- Test — Restore power and run a heating call; verify the board steps through its sequence and initiates defrost normally.
Signs You Need a Replacement
- Outdoor coil ices over heavily and heating output drops.
- Unit never enters defrost, or stays stuck in defrost.
- Reversing valve or outdoor fan won't switch on command.
- No or erratic 24V control output to the contactor and 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