ICP Transformer for WAHA18074A1 – 40VA 208/230V to 24V | Ships Today

Overview

This genuine OEM control transformer (part number 1173844) steps 208/230V line voltage down to the 24V required to power the thermostat, control board, relays, and contactor in the ICP/Tempstar/Heil WAHA18074A1. Rated at 40VA, it feeds the low-voltage control circuit that runs the whole system. A failed transformer is one of the most common no-heat / no-cool causes: when it opens or shorts, the thermostat goes dark and nothing energizes. Transformers typically fail from a low-voltage short, a seized contactor coil pulling excess current, or age and heat.

Specifications

Compatibility

Direct OEM replacement for the ICP WAHA18074A1 air handler and the matching Tempstar, Heil, and Comfortmaker units using the same 40VA control transformer. Verify your existing transformer is marked 1173844 with a 208/230V primary and 24V secondary before installing.

Installation Guide

1. Safety First – Disconnect power at the breaker and confirm zero voltage at the control box with a multimeter.
2. Access – Remove the control/electrical service panel.
3. Document – Photograph the primary and secondary wiring before disconnecting any leads.
4. Remove – Disconnect all primary and secondary leads, then unbolt the transformer from its mounting bracket.
5. Install – Mount the new transformer, match the 208/230V primary leads to line voltage and the 24V secondary to the control circuit per your photo.
6. Test – Restore power and confirm 24V across the secondary and a live thermostat.

Signs You Need a Replacement

• Thermostat is blank and the system is completely dead
• No 24V reading across the secondary terminals (R to C)
• Transformer is hot, buzzing, or smells burnt
• Repeated blown low-voltage fuse or tripped breaker on the control circuit

Shipping & Returns

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