ICP 24V Transformer for ZAMB001AHA3 — SPST 40VA Control | Ships Today

Overview

This OEM 24V control transformer (ICP part #1057251) supplies the low-voltage power that operates the thermostat, relays, and control circuits in your air handler or furnace. Rated at 40VA, it steps line voltage down to 24V to drive the SPST control loop. When a control transformer fails, the entire 24V circuit goes dead: the thermostat screen blanks, contactors and relays will not energize, and the system will not start. Common failure causes include a shorted secondary winding, an overloaded control circuit, or repeated voltage spikes that overheat and open the windings.

Specifications

Compatibility

Direct-fit replacement for ICP, Tempstar, Heil, and Comfortmaker equipment that uses the 1057251 control transformer, including model ZAMB001AHA3. Confirm the primary voltage and VA rating against your existing transformer before installing.

Installation Guide

1. Safety First — Disconnect power and verify zero voltage with a multimeter.
2. Access — Remove the control-box/service panel to reach the transformer.
3. Document — Photograph the primary and secondary wiring before disconnecting.
4. Remove — Disconnect the leads, unbolt the transformer from its mounting bracket, and remove it.
5. Install — Mount the new transformer, reconnect primary and secondary leads per your photo.
6. Test — Restore power and confirm 24V across the secondary and normal control operation.

Signs You Need a Replacement

• Blank thermostat or no 24V at the control board
• Contactors and relays will not pull in
• Repeatedly blown low-voltage fuse
• Transformer is hot, buzzing, or visibly scorched

Shipping & Returns

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