ICP 40VA Transformer for RGS240HFFA0AAAA — 24V Control Output | Ships Today

Overview

This OEM control transformer supplies the 24-volt low-voltage power that runs the entire control circuit on the ICP/Heil/Tempstar RGS240HFFA0AAAA gas furnace. It steps the incoming line voltage down to 24V to energize the thermostat, ignition control, gas valve, and the DPDT and DPST control relays (OEM 1183814 and 1178205) that switch the blower and ignition stages. When the transformer fails, the entire control board goes dark — the furnace will not respond to a thermostat call even though high-voltage power is present at the unit. A 40VA rating provides the inrush capacity these multi-relay control circuits demand, so the secondary voltage does not sag when the gas valve and relays pull in together. Common failure symptoms include a repeatedly blown low-voltage fuse, no 24V reading across the secondary terminals, an unresponsive thermostat, or a buzzing transformer that overheats under load.

Specifications

Compatibility

Engineered for the ICP/Heil/Tempstar RGS240HFFA0AAAA rooftop gas furnace and shared-platform RGS240 family units that use the same 24V control architecture. Always confirm the VA rating and terminal layout against your existing transformer before installing.

Installation Guide

1. Safety First — Disconnect power at the unit disconnect and verify zero voltage at the transformer with a multimeter.
2. Access — Remove the control-compartment service panel.
3. Document — Photograph every primary and secondary wire connection before disconnecting.
4. Remove — Disconnect the primary and secondary leads and unbolt the old transformer from its mounting bracket.
5. Install — Mount the new transformer, then reconnect the primary and secondary leads exactly per your photo.
6. Test — Restore power, confirm 24V across the secondary, and run a full heat cycle to verify the relays and gas valve energize.

Signs You Need a Replacement

• Furnace is completely unresponsive to thermostat calls while line voltage is present.
• Low-voltage control fuse blows immediately or repeatedly.
• No 24V output measured across the secondary terminals.
• Transformer hums loudly, overheats, or smells burnt.

Shipping & Returns

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