Tempstar Defrost Control Board for T2H318GKA100 — Heat Pump OEM 1173636 | Ships Today
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Overview
This is the genuine OEM Tempstar defrost control board (part number 1173636) for the T2H318GKA100 heat pump. The defrost control board is the brain of your heat pump's defrost cycle: it monitors coil temperature and run time, then initiates and terminates defrost to clear ice from the outdoor coil during heating mode. It also coordinates the reversing valve and outdoor fan during defrost. When this board fails, the heat pump can either skip defrost entirely — letting the coil ice over and killing efficiency — or get stuck in defrost, blowing cold air indoors and triggering auxiliary heat far more than necessary. Common failure symptoms include a permanently iced outdoor unit, no auxiliary heat staging, intermittent no-heat calls, and visible scorch marks or relay chatter on the board itself.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP / Heil) |
| Fits Model | T2H318GKA100 |
| Application | Heat Pump Defrost Control |
| Fitment | OEM Replacement |
Compatibility
This board is the factory-specified defrost control for the Tempstar T2H318GKA100 heat pump and the shared ICP / Heil / Comfortmaker platforms that use part 1173636. Always confirm the part number printed on your existing board before ordering, as defrost boards across the ICP family look similar but differ in timing logic and terminal layout.
Installation Guide
- Safety First — Disconnect power at the outdoor disconnect and the breaker, then verify zero voltage at the board with a multimeter.
- Access — Remove the control-box access panel on the outdoor unit.
- Document — Photograph every wire and terminal position before disconnecting anything.
- Remove — Label and disconnect the low-voltage and line-voltage leads, then unclip or unscrew the old defrost board from its standoffs.
- Install — Mount the new board on the standoffs and reconnect each wire exactly as photographed, including the defrost thermostat and sensor leads.
- Test — Restore power and confirm normal heating operation, then verify a defrost cycle initiates and terminates correctly.
Signs You Need a Replacement
- Outdoor coil ices over and never clears during heating mode
- Unit gets stuck in defrost, blowing cold air indoors
- Auxiliary/emergency heat runs constantly or won't stage
- Visible burn marks, corrosion, or chattering relays 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