ICP Transformer for RH5420483 — 40VA 208/240V to 24V | Ships Today

Overview

This is a genuine OEM 40VA control transformer (part number 1540372) for the ICP/Tempstar/Heil RH5420483. It steps the incoming 208/240V line voltage down to the 24V low-voltage control circuit that powers the thermostat, contactor coil, relays, and safety controls. If this transformer fails, the entire low-voltage control system loses power and the equipment will not start. Typical failure symptoms include a dead thermostat, no 24V at the control board, a buzzing or scorched transformer, or a repeatedly blown low-voltage fuse from a shorted secondary winding. This is a dual-primary 208/240V unit with a 24V, 40VA secondary output — the correct rating for this equipment.

Specifications

Compatibility

Factory-correct replacement for ICP, Tempstar, Heil, Comfortmaker, and related International Comfort Products units built around the RH5420483 platform. Confirm the printed VA and voltage on your existing transformer match 40VA and 208/240V to 24V before installing.

Installation Guide

1. Safety First — Disconnect power at the disconnect and breaker, then verify zero voltage with a multimeter on both line and 24V circuits.
2. Access — Remove the service/control panel to expose the transformer and control wiring.
3. Document — Photograph every wire and terminal before disconnecting anything.
4. Remove — Label and disconnect the primary and secondary leads, then unbolt the transformer from its mounting bracket.
5. Install — Mount the new transformer, match the primary taps to your supply voltage (208 vs 240), and reconnect the secondary per your photo.
6. Test — Restore power and confirm 24V across the secondary terminals; the thermostat and controls should energize normally.

Signs You Need a Replacement

• No 24V output measured at the secondary terminals.
• Thermostat is dark and the system won't respond to a call.
• Repeatedly blown low-voltage fuse or breaker on the control circuit.
• Visible scorching, melted insulation, or constant buzzing from the transformer.

Shipping & Returns

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