Tempstar Defrost Control Board for TCH242AKAA — Heat Pump | Ships Today

Overview

This genuine OEM defrost control board (part number 1086070, "DEFROST CONTROL BOARD X") is the brain of the defrost cycle on the Tempstar TCH242AKAA heat pump. It monitors the defrost thermostat and timer logic, then commands the reversing valve, condenser fan, and auxiliary heat to clear frost from the outdoor coil during heating operation. A failed board is a common cause of a heat pump that ices over, never defrosts, locks into defrost, or short-cycles in cold weather. Because it sequences the 24V control circuit, board failure can also leave the outdoor unit completely unresponsive.

Specifications

Compatibility

Direct-fit replacement for the Tempstar TCH242AKAA heat pump. Shared across equivalent ICP-family condensing units (Heil, Comfortmaker, Arcoaire) using the same defrost logic. Confirm OEM number 1086070 against your existing board, as defrost boards vary by series and timer pin settings.

Installation Guide

1. Safety First — Disconnect power at the disconnect and breaker, then verify zero voltage with a multimeter.
2. Access — Remove the condenser unit's control/electrical panel to expose the board.
3. Document — Photograph all wiring harness and terminal connections, and note the defrost-timer jumper/pin setting.
4. Remove — Release the standoffs/screws and unplug each connector from the failed board.
5. Install — Mount the new board, match the defrost-timer pin setting, and reconnect every harness per your photo.
6. Test — Restore power, initiate a heating call, and force/observe a defrost cycle to confirm correct sequencing.

Signs You Need a Replacement

• Outdoor coil ices over and never defrosts
• Heat pump stuck in continuous defrost
• Short-cycling or no auxiliary heat during defrost
• Outdoor unit unresponsive to heating calls

Shipping & Returns

Ships same day on orders placed before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.