Tempstar Defrost Control Board for T4H736GKB100 — 24V Heat Pump | Ships Today
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Overview
This genuine OEM defrost control board (part number 1173636) is the brain of the Tempstar T4H736GKB100 heat pump's defrost cycle. In heating mode, the outdoor coil accumulates frost; the defrost board monitors elapsed run time and the defrost thermostat, then periodically reverses the system into a brief cooling cycle to melt that frost while energizing supplemental heat for comfort. The board manages the reversing valve, outdoor fan, and defrost timing intervals. When it fails, the heat pump can ice over heavily in winter, run inefficiently, short-cycle, or fail to switch between heating and cooling. Because it carries 24V control logic and switches multiple outputs, a damaged board is a frequent cause of poor cold-weather heat-pump performance.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP / Heil) |
| Control Voltage | 24 VAC |
| Function | Defrost timing, reversing valve & fan control |
| Fits Model | T4H736GKB100 |
Compatibility
Directly fits the Tempstar T4H736GKB100 heat pump and other ICP-family (Heil, Comfortmaker, Tempstar) heat pumps that specify OEM defrost board 1173636. Confirm the part number printed on your existing board before ordering.
Installation Guide
- Safety First — Disconnect power at the outdoor disconnect and breaker. Verify zero voltage with a multimeter.
- Access — Remove the condenser unit's electrical access panel.
- Document — Photograph every wire and connector on the board before disconnecting; label as needed.
- Remove — Disconnect the low-voltage and line connections, then unscrew or unclip the old board from its standoffs.
- Install — Mount the new board and reconnect each lead exactly per your photo, seating connectors fully.
- Test — Restore power and confirm normal heating operation; if accessible, initiate a forced defrost to verify the cycle.
Signs You Need a Replacement
- Outdoor coil ices over and won't clear in heating mode
- Heat pump won't switch between heating and cooling
- Short-cycling or no defrost cycle at all
- Auxiliary/emergency heat runs constantly or never engages
Shipping & Returns
Ships same day on orders placed 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