ICP Defrost Control Board for YC048H — 24V Heat Pump Defrost Timer | Ships Today

Overview

The ICP defrost control board (OEM part #34332100) is the brain of the defrost cycle on your YC048H heat pump. Operating on 24 volts, this board monitors coil temperature and run time, then commands the reversing valve and outdoor fan to clear frost and ice from the outdoor coil during heating mode. When this board fails, the unit can frost over completely, stop heating, run the outdoor fan during defrost, or short-cycle. A faulty defrost board is one of the most common causes of poor heat-pump performance in cold weather. This is a genuine OEM replacement, so timing logic, terminal layout, and relay ratings match the original exactly.

Specifications

Compatibility

Designed as a direct-fit replacement for the ICP / Tempstar / Heil YC048H heat pump and other units that originally shipped with OEM board 34332100. Always confirm the part number printed on your existing board before ordering, as ICP used several board revisions across model years.

Installation Guide

1. Safety First — Disconnect power at the outdoor disconnect and breaker, then verify zero voltage at the board with a multimeter.
2. Access — Remove the condenser control-panel access cover.
3. Document — Photograph every wire and terminal position before disconnecting anything.
4. Remove — Label and unplug the low-voltage and line-voltage connections, then unscrew the old board from its standoffs.
5. Install — Mount the new board on the standoffs and reconnect each wire to the matching terminal per your photo. Set defrost timing pins/jumpers to match the original.
6. Test — Restore power and run a heat cycle; force or wait for a defrost to confirm the reversing valve energizes and the outdoor fan stops.

Signs You Need a Replacement

• Outdoor coil ices over and never clears in heating mode
• Heat pump stops producing heat or runs auxiliary/strip heat constantly
• Outdoor fan keeps running during a defrost cycle
• No 24V output to the reversing valve or defrost relay chatter

Shipping & Returns

Ships same day on orders placed before 3 PM CST. 30-day returns on unused parts. Backed by the National HVAC Parts fitment guarantee — if it doesn't fit your YC048H, we'll make it right.