Tempstar Defrost Control Board for T4H436GKC200 — OEM 1173636 | Ships Today
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Overview
This is a genuine OEM Defrost Control Board (part number 1173636) for the Tempstar T4H436GKC200 heat pump. The defrost board is the brain of the outdoor unit's heating operation: it monitors the defrost thermostat and a timed interval to determine when frost has built up on the outdoor coil, then reverses the system into defrost mode, energizes the reversing valve, stops the outdoor fan, and brings on auxiliary heat. A failed defrost board causes the outdoor coil to ice over (killing heating capacity), or causes the unit to defrost too often or not at all. Boards fail from voltage surges, relay burnout, and corrosion.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP / Heil) |
| Control Voltage | 24V |
| Function | Heat-pump defrost cycle management |
| Fit | OEM Direct Replacement |
Compatibility
Direct-fit OEM replacement for the Tempstar T4H436GKC200 and other ICP-family heat pumps (Tempstar, Heil, Comfortmaker) specifying board 1173636. Defrost timing pins/jumpers must be set to match your original board — note the existing jumper position before swapping.
Installation Guide
- Safety First — Disconnect power at the disconnect and verify zero voltage with a multimeter.
- Access — Remove the condenser control-box access panel.
- Document — Photograph every connector, wire color/terminal, and the defrost-timing jumper position.
- Remove — Unplug the low-voltage and line-voltage connectors and unscrew/unclip the board from its standoffs.
- Install — Mount the new board, set the timing jumper to match the original, and reconnect all wiring per your photo.
- Test — Restore power and initiate a defrost test (per the board's forced-defrost procedure) to confirm correct operation.
Signs You Need a Replacement
- Outdoor coil ices over and the unit never defrosts in heating mode.
- Unit defrosts constantly or at the wrong times.
- No 24V output to the reversing valve or fan during defrost.
- Visible burnt relay, scorch marks, or corroded traces 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