Tempstar Defrost Control Board for TXH548GKA100 — Heat Pump Timer Board | Ships Today
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Overview
This OEM defrost control board (Part #1173636) is the brain of the defrost cycle on your Tempstar TXH548GKA100 heat pump. In heating mode the outdoor coil accumulates frost; this board monitors the defrost thermostat and run time, then temporarily reverses the unit to melt ice off the coil before returning to normal heating. It coordinates the reversing valve, condenser fan, and auxiliary heat during each cycle. When the board fails, the outdoor coil ices over and heating efficiency collapses — or the system gets stuck defrosting and blows cold air indoors. A blank or unlit board, no defrost activity, or a unit that never exits defrost are all classic symptoms.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1173636 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP / Heil) |
| Application | Heat Pump Defrost Management |
| Control Voltage | 24 VAC |
Compatibility
Direct OEM replacement for the Tempstar TXH548GKA100 heat pump. The 1173636 defrost board is used across multiple ICP-family heat pump models (Heil, Comfortmaker, Arcoaire). Match the part number and connector layout to your existing board before installing.
Installation Guide
- Safety First — Disconnect power at the disconnect and breaker, then verify zero voltage with a multimeter.
- Access — Remove the outdoor unit's electrical/control panel.
- Document — Photograph every wire and connector position before disconnecting.
- Remove — Unplug the harnesses and release the board from its standoffs/mounting screws.
- Install — Seat the new board, transfer any jumper/dip-switch settings, and reconnect each harness per your photo.
- Test — Restore power and verify a normal heating call, then confirm a defrost cycle initiates and terminates correctly.
Signs You Need a Replacement
- Outdoor coil freezes over and stays iced in heating mode.
- Unit never enters defrost, or gets stuck in defrost.
- Cold air blows indoors during heating because the cycle won't end.
- Board LEDs are dark or showing a fault/error code.
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