Tempstar Defrost Control Board for T4H548GKB100 — OEM 1173636 Heat Pump Board | Ships Today
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Overview
This is a genuine OEM defrost control board (part number 1173636) for the Tempstar T4H548GKB100 heat pump. The defrost control board manages the heat pump's defrost cycle — it monitors outdoor coil temperature and accumulated run time, then initiates a defrost to clear frost and ice from the outdoor coil during winter heating. It coordinates the reversing valve, outdoor fan, and auxiliary heat to maintain efficient operation in cold conditions. A failed board can leave the coil iced over, stuck in defrost, short-cycling, or unable to heat. The board runs on a 24V control circuit and carries the standard Tempstar heat pump defrost timing logic.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar |
| Control Voltage | 24V |
| Application | Heat Pump Outdoor Unit |
| Fitment | OEM Direct Replacement |
Compatibility
Direct OEM fit for the Tempstar T4H548GKB100 heat pump and shared across related ICP-family outdoor units (Heil, Comfortmaker, and other Tempstar models) using the same defrost control platform. Confirm your existing board reads 1173636 before installing.
Installation Guide
- Safety First — Disconnect power at the disconnect and breaker, and verify zero voltage with a multimeter before handling wiring.
- Access — Remove the outdoor unit's electrical access panel.
- Document — Photograph every wire and connector on the existing board first.
- Remove — Label and unplug the harnesses, remove the mounting screws, and lift out the old board.
- Install — Mount the new 1173636 board, reconnect each harness exactly per your photos, and seat all connectors fully.
- Test — Restore power, confirm the unit heats, and force a defrost cycle to verify the board commands the reversing valve and fan.
Signs You Need a Replacement
- Outdoor coil ices over and never enters defrost
- Unit gets stuck in defrost and won't return to heating
- No 24V output to the reversing valve or outdoor fan
- Scorched relays, corrosion, or burn marks on the 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