ICP Defrost Control Board for WCH3484GKA1 — Heat Pump Defrost Board | Ships Today

Overview

This genuine OEM defrost control board (OEM part number 1173636) manages the defrost cycle on ICP, Heil, and Tempstar heat pumps. The board monitors the defrost thermostat and a timed interval, then initiates a defrost cycle — reversing the valve, stopping the outdoor fan, and energizing auxiliary heat — to melt frost off the outdoor coil during cold-weather operation. It also coordinates compressor timing and lockout protection. A failed defrost board leaves the outdoor coil iced over, killing heating efficiency and risking compressor damage.

Specifications

Compatibility

Directly fits ICP/Heil/Tempstar heat pump model WCH3484GKA1 and other units using this defrost control board. Confirm the board layout, connector positions, and defrost timing pin options match your existing board before installing.

Installation Guide

1. Safety First — Disconnect power at the disconnect and breaker, then verify zero voltage with a multimeter.
2. Access — Remove the condenser/heat pump service panel to reach the control board.
3. Document — Photograph every connector and the defrost timing jumper position before removing anything.
4. Remove — Unplug each harness, note the defrost thermostat and sensor leads, and unscrew the board from its standoffs.
5. Install — Mount the new board, reconnect every harness per your photo, and set the defrost timing pin to match the original.
6. Test — Restore power, run the unit in heating, and (if needed) force a defrost test to confirm the cycle initiates and terminates correctly.

Signs You Need a Replacement

• Outdoor coil ices up and never defrosts in heating mode.
• System runs constant defrost or won't exit defrost.
• No response from the board despite proper 24V input.
• Visible burnt traces, scorched relays, or a failed onboard relay.

Shipping & Returns

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