ICP 40VA Transformer 120V to 24V for SUP18M2401AIA – OEM L01F009 w/ Relay | Ships Today

Overview

This OEM control package for the ICP SUP18M2401AIA includes the genuine L01F009 40VA transformer (120V primary to 24V secondary) and the matching L01H009 24VAC relay. The transformer steps line voltage down to the 24V the control circuit, thermostat, and relay coils run on — without it, nothing downstream powers up. The L01H009 relay uses that 24V signal to switch a higher-current load. A failed transformer is one of the most common no-heat / no-cool calls: a shorted secondary or blown internal fuse kills all low-voltage power, so the thermostat goes dark and the unit is completely unresponsive even though line power is present.

Specifications

Compatibility

Built for the ICP SUP18M2401AIA and shared across ICP-family units sold under Heil, Tempstar, and Comfortmaker that use a 120V-primary, 40VA control transformer. Confirm your primary voltage is 120V (not 208/240) before ordering.

Installation Guide

1. Safety First – Disconnect power and verify zero voltage with a multimeter at both the line and 24V terminals.
2. Access – Remove the control-compartment service panel.
3. Document – Photograph the primary and secondary leads and the relay terminals before disconnecting.
4. Remove – Unscrew the old transformer and relay, then disconnect the leads.
5. Install – Mount the new transformer and relay, wiring the 120V primary and 24V secondary exactly per your photo.
6. Test – Restore power and confirm 24 VAC at the secondary and proper relay pull-in on a thermostat call.

Signs You Need a Replacement

• Thermostat screen is blank and the unit is fully unresponsive
• No measurable 24 VAC at the transformer secondary
• Transformer hums loudly, runs hot, or smells burnt
• Relay chatters or fails to pull in on a call

Shipping & Returns

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