Tempstar 40VA Transformer 208/240V to 24V for TEB12K50RTA — OEM | Ships Today

Overview

This is the OEM 40VA control transformer for the Tempstar TEB12K50RTA, stepping 208/240V line voltage down to 24V to power the unit's control circuit, relays, and thermostat (OEM 1056899, TRANS 208/240>24 40VA). When a transformer fails — usually from a shorted control wire or an overloaded 24V circuit — the entire low-voltage system goes dead: no thermostat response, no relay pull-in, and no operation despite line power being present. This listing covers the transformer and its companion control relays (OEM 1053004, RELAY 24V; OEM 1060940, RELAY 24V DPST) used in this model's control package.

Specifications

Compatibility

Designed for the Tempstar TEB12K50RTA. The 40VA 208/240V-to-24V transformer is shared across many ICP-family (Heil, Comfortmaker, Tempstar) units, but verify part number 1056899 and your unit's primary voltage before ordering.

Installation Guide

1. Safety First — Disconnect power at the breaker; verify zero voltage with a multimeter.
2. Access — Remove the control/electrical panel to expose the transformer and relays.
3. Document — Photograph all primary (line) and secondary (24V) leads before disconnecting.
4. Remove — Unbolt the transformer from the bracket and disconnect all leads; note the 208 vs 240 primary tap if applicable.
5. Install — Mount the new transformer, match the primary tap to your supply voltage, and reconnect per your photos.
6. Test — Restore power and confirm ~24V across the secondary and proper relay pull-in.

Signs You Need a Replacement

• No 24V at the control board or thermostat with line power present.
• Tripped or blown low-voltage fuse that recurs.
• Burnt smell or visibly scorched transformer windings.
• Relays fail to energize and the unit won't start.

Shipping & Returns

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