ICP Transformer for WAHA24074A1 — 40VA 208/230V to 24V | Ships Today

Overview

This is a genuine OEM 40VA control transformer (OEM part #1173844) for the ICP / Tempstar / Heil model WAHA24074A1 air handler. The transformer steps down 208/230V line voltage on the primary to 24V on the secondary, supplying the low-voltage control circuit that powers the thermostat, relays, contactor coil, and control board. If the transformer fails, the 24V control system goes dead and the equipment will not respond to any heating or cooling call. Common failure symptoms include a blank/unresponsive thermostat, no measurable 24V output, a repeatedly blown control fuse, or a transformer that buzzes, runs hot, or smells burnt. A shorted control wire or failed downstream component often destroys the transformer, so inspect the entire 24V circuit when replacing it.

Specifications

Compatibility

Engineered as a direct-fit replacement for ICP model WAHA24074A1 and shared across many ICP-family air handlers and furnaces sold under the Tempstar, Heil, Comfortmaker, and Arcoaire brands that use a 208/230V to 24V 40VA control transformer. Always confirm the primary/secondary voltage and VA rating against the unit being serviced.

Installation Guide

1. Safety First — Disconnect power at the breaker and verify zero voltage with a multimeter before touching any wiring.
2. Access — Remove the service/control panel to expose the transformer.
3. Document — Photograph all primary and secondary wire connections before disconnecting.
4. Remove — Note the primary tap used (208 vs 230), disconnect the leads, and unbolt the old transformer from the mounting bracket.
5. Install — Mount the new transformer, land the primary leads on the matching voltage tap, and reconnect the 24V secondary per your photo.
6. Test — Restore power and confirm 24V (±10%) at the secondary and normal thermostat operation.

Signs You Need a Replacement

• Thermostat screen is blank and the system is completely unresponsive.
• No 24V reading at the transformer secondary terminals.
• Repeatedly blown low-voltage fuse or breaker on the control circuit.
• Transformer is hot to the touch, buzzing, or has a burnt smell.

Shipping & Returns

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