ICP 24V Transformer for ZAMA017AHA3 — SPST 40VA Control | Ships Today

Overview

This OEM 24V control transformer (ICP part #1057251) provides the low-voltage power that runs the thermostat, relays, and control circuits in your air handler or furnace. Rated at 40VA, it steps line voltage down to a stable 24V for the SPST control loop. A failed control transformer kills the entire 24V circuit: the thermostat goes dark, relays and contactors will not energize, and the system will not start. Typical causes are a shorted secondary, an overloaded control circuit, or heat-related winding failure from voltage surges.

Specifications

Compatibility

Direct-fit replacement for ICP, Tempstar, Heil, and Comfortmaker equipment that uses the 1057251 control transformer, including model ZAMA017AHA3. Verify primary voltage and VA rating against the original part 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 bracket, and remove it.
5. Install — Mount the new transformer and 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
• Relays and contactors fail to pull in
• Low-voltage fuse blows repeatedly
• Transformer is hot, buzzing, or scorched

Shipping & Returns

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