Tempstar 40VA Transformer for TEB12R34RTA — 277V to 24V Control | Ships Today

Overview

This genuine OEM 40VA control transformer (part 1091226) steps 277V line power down to the 24V needed to run the contactors, relays, and thermostat circuit on the Tempstar TEB12R34RTA. This listing also covers the associated 24V relays used in the same control circuit — 1053004 (RELAY 24V) and 1060940 (RELAY 24V DPST). The transformer is the power source for the entire low-voltage control system; when it fails, nothing in the 24V circuit energizes — no contactor pull-in, no fan, no compressor — even though line voltage is present. A blown transformer is often the result of a shorted secondary or a stuck relay drawing excess current.

Specifications

Compatibility

Direct factory replacement for the 277V control circuit on the Tempstar / Heil / ICP TEB12R34RTA. The 277V primary is specific to this PTAC's electrical configuration — confirm your line voltage before ordering.

Installation Guide

1. Safety First — Disconnect power and verify zero voltage at the transformer primary with a multimeter.
2. Access — Remove the service panel to reach the control box.
3. Document — Photograph the primary and secondary wiring before disconnecting.
4. Remove — Disconnect the leads, unbolt the transformer from its bracket.
5. Install — Mount the new transformer, wire 277V to the primary and 24V to the secondary exactly as photographed.
6. Test — Restore power and confirm 24V across the secondary, then verify control circuit operation.

Signs You Need a Replacement

• No 24V control power despite live line voltage
• Contactor and relays will not pull in
• Visible scorching, bulging, or burnt-insulation smell
• Tripped or blown low-voltage fuse that recurs

Shipping & Returns

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