ICP Defrost Control Board for YK042G2 — Heat Pump | Ships Today

Overview

This is the genuine OEM defrost control board (part number 34332101) for the ICP / Tempstar / Heil YK042G2 heat pump. The defrost board is the brain of the outdoor unit's winter operation: it monitors coil temperature and run time, then periodically energizes the reversing valve and shuts off the outdoor fan to melt frost from the coil before returning to heating. It also coordinates the contactor and, in many configurations, auxiliary heat staging. When this board fails, the heat pump may ice over solid, never run a defrost cycle, defrost too often, or fail to start in heat mode at all — leading to poor heating, high energy bills, and possible coil or compressor damage. Replacing the board restores correct, efficient defrost timing.

Specifications

Compatibility

Designed for the ICP / Tempstar / Heil YK042G2 heat pump and other units using this defrost control board. Match the part number and connector layout to your original 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 service panel to expose the control board.
3. Document — Photograph every wire, plug, and the defrost timing jumper/pin setting before disconnecting.
4. Remove — Unplug the harnesses, release the mounting standoffs, and lift out the old board.
5. Install — Snap in the new board, set the defrost time jumper to match the original, and reconnect each harness per your photo.
6. Test — Restore power, run the unit in heating, and confirm normal operation and a proper forced-defrost cycle.

Signs You Need a Replacement

• Outdoor coil ices over and never defrosts
• Unit defrosts too frequently or at the wrong times
• No heat-pump operation despite a heat call
• Burn marks, corrosion, or failed relays on the board

Shipping & Returns

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