Tempstar Defrost Control Board for TCH424AKA1 — OEM 1086070 | Ships Today
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Overview
This genuine OEM defrost control board (part number 1086070) is the brain of the Tempstar TCH424AKA1 heat pump's outdoor section. It monitors coil temperature and run time, then initiates and terminates defrost cycles to clear frost from the outdoor coil in cold weather. The board also sequences the compressor contactor, condenser fan, reversing valve coil, and auxiliary/emergency heat hand-off. When this board fails, the heat pump may ice over, fail to defrost, short-cycle, or lose heating and cooling control entirely. A new OEM board restores correct defrost timing and protects the compressor.
Specifications
| Spec | Value |
|---|---|
| Part Number | 1086070 |
| Type | Defrost Control Board |
| Brand | Tempstar (ICP / Heil) |
| Control Voltage | 24V |
| Function | Defrost Timing, Reversing Valve & Contactor Control |
| Application | Heat Pump Outdoor Unit |
| Fitment | OEM Direct Replacement |
Compatibility
Direct-fit OEM replacement for the Tempstar TCH424AKA1 heat pump. This defrost board is used across many ICP-family heat pumps (Tempstar, Heil, Comfortmaker) of the same generation. Confirm the printed board part number and connector layout against your existing board before ordering.
Installation Guide
- Safety First — Disconnect power at the breaker and pull the outdoor disconnect, then verify zero voltage with a multimeter.
- Access — Remove the condenser service panel to reach the control box and board.
- Document — Photograph every connector, wire color, and terminal position before unplugging anything.
- Remove — Unplug each connector and sensor lead, then release the board's standoffs or mounting screws and lift it out.
- Install — Mount the new board on the standoffs and reconnect each plug and sensor exactly per your photos, checking any defrost-timing jumper/DIP settings.
- Test — Restore power, confirm normal heating/cooling operation, and verify the board enters and exits a defrost cycle correctly.
Signs You Need a Replacement
- Outdoor coil ices over and the unit never defrosts.
- Heat pump short-cycles or won't switch between heat and cool.
- No 24V output to the contactor, fan, or reversing valve.
- Visible scorch marks, burned relays, or a cracked board.
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