ICP 40VA Transformer for SUP15M2401AIA — 120/24V w/ Relay | Ships Today

Overview

This is the genuine ICP/Tempstar/Heil 40VA step-down transformer (OEM part L01F009) for the SUP15M2401AIA, paired with the matching 24VAC control relay (L01H009, AG90-23242-024W). The transformer converts the unit's 120-volt line power down to the 24-volt control voltage that runs the thermostat, control board, relays, and contactor coil. If the transformer fails — from an overload, short, or simple age — the entire low-voltage circuit goes dead and the unit will not respond to any call for heating or cooling. The included 24VAC relay handles control-circuit switching. Together they restore stable, factory-rated 24V control power.

Specifications

Compatibility

Direct OEM-fit replacement for the ICP SUP15M2401AIA and other Tempstar/Heil/Comfortmaker units that use a 120V-to-24V 40VA control transformer. Confirm your primary voltage is 120V and the VA rating matches before ordering.

Installation Guide

1. Safety First — Disconnect power and verify zero voltage with a multimeter.
2. Access — Remove the electrical service panel.
3. Document — Photograph the primary and secondary wiring before disconnecting.
4. Remove — Disconnect the line and 24V leads, then unbolt the failed transformer and relay from the panel.
5. Install — Mount the new transformer and relay, reconnect the 120V primary and 24V secondary leads per your photos.
6. Test — Restore power and confirm a steady 24VAC reading on the secondary and normal operation.

Signs You Need a Replacement

• No 24V control power — thermostat and board are completely dead.
• Repeatedly blown low-voltage fuses or tripped breaker.
• Buzzing, overheating, or a burnt smell from the transformer.
• Measured secondary voltage is missing or far below 24VAC.

Shipping & Returns

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