ICP 24V Transformer for RGS243HFAA0AAAA — 40 VA Control Power | Ships Today
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Overview
This OEM 24-volt control transformer steps line voltage down to the 24 VAC low-voltage power that the control circuit on your ICP RGS243HFAA0AAAA unit needs to energize relays, contactors, and the thermostat loop. Rated at 40 VA, it supplies the 24V DPDT and DPST control relays (OEM 1183814 and 1178205) that switch the unit's stages. When a transformer fails, the entire low-voltage side goes dead: the thermostat screen blanks, contactors will not pull in, and the system simply does nothing on a call for heat or cool. A buzzing transformer, a tripped low-voltage fuse that blows again immediately, or zero volts across the secondary terminals all point to a transformer or a short downstream of it.
Specifications
| Spec | Value |
|---|---|
| Part Numbers | 1183814 (Relay 24V DPDT), 1178205 (Relay 24V DPST) |
| Type | Control Transformer |
| Brand | ICP / Tempstar / Heil |
| Rating | 40 VA |
| Secondary Voltage | 24 VAC |
| Fit | OEM Replacement |
Compatibility
Engineered as a direct OEM fit for the ICP / Tempstar / Heil RGS243HFAA0AAAA and the broader RGS243 control platform. Always confirm your unit's VA rating and secondary voltage against the rating plate before installing.
Installation Guide
- Safety First — Disconnect power at the breaker and verify zero voltage with a multimeter before touching any wiring.
- Access — Remove the control/service panel to expose the low-voltage section.
- Document — Photograph all primary and secondary wire connections before disconnecting anything.
- Remove — Label and disconnect the primary and 24V secondary leads, then unbolt the failed transformer from its mounting bracket.
- Install — Mount the new transformer, reconnect primary and secondary leads per your photo, and confirm the low-voltage fuse is intact.
- Test — Restore power and verify 24 VAC across the secondary terminals and that contactors and relays energize on a call.
Signs You Need a Replacement
- Thermostat screen is blank and the system is completely unresponsive.
- Repeatedly blown low-voltage (3–5A) fuse.
- No 24 VAC measured across the secondary terminals.
- Audible buzzing, scorched smell, or visible burn marks on the transformer body.
Shipping & Returns
Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.
Shipping Information
- Orders placed before 3PM CST ship same business day
- Standard delivery: 2-5 business days
- Express shipping available at checkout
- Free shipping on orders over $75
- Tracking number emailed upon shipment
Return Policy
- 30-day returns on unused parts in original packaging
- Electrical parts (capacitors, contactors, control boards) are final sale once installed
- Email info@nationalhvacparts.com to initiate a return
- Refunds processed within 5-7 business days