Tempstar Defrost Control Board for T4H318GKD300 — 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 T4H318GKD300 heat pump condensing unit. The defrost control board manages the entire defrost cycle — it reads outdoor coil temperature and tracks compressor run time, then temporarily reverses the system into cooling mode to clear frost and ice from the outdoor coil during cold-weather heating. It sequences the reversing valve, condenser fan, and compressor so the unit recovers efficiently and protects itself. A failed board commonly leaves the coil iced solid, kills heating output, or causes nuisance compressor lockouts. Operating on 24V control logic, this is a direct factory replacement.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP/Heil) |
| Control Voltage | 24V |
| Application | Heat Pump Defrost Cycle |
| Fitment | OEM Direct Replacement |
Compatibility
Direct-fit OEM replacement for the Tempstar T4H318GKD300 heat pump. The 1173636 board is also used across many ICP-family (Tempstar, Heil, Comfortmaker, Arcoaire) heat pump models sharing this control platform. Verify your existing board's part number before ordering.
Installation Guide
- Safety First — Disconnect power at the outdoor disconnect and verify zero voltage with a multimeter before handling any wiring.
- Access — Remove the condenser unit's control-panel access cover.
- Document — Photograph every wire and terminal on the existing board before disconnecting.
- Remove — Label and disconnect the low-voltage and sensor leads, release the board standoffs or screws, and lift out the old board.
- Install — Mount the new 1173636 board and reconnect each lead exactly as shown in your photos, including the defrost sensor.
- Test — Restore power, confirm normal heating, and verify the board initiates and ends a defrost cycle correctly.
Signs You Need a Replacement
- Outdoor coil freezes over and the unit never defrosts
- System won't enter defrost, or stays stuck in defrost
- Compressor short-cycles or locks out during heating
- Scorched, corroded, or visibly damaged board components
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