Tempstar Control Transformer for TEB07R25RTA — 277V to 24V 40VA | Ships Today

Overview

This is the OEM low-voltage control transformer for the Tempstar TEB07R25RTA packaged terminal unit. It steps the 277V line-voltage supply down to the 24V control voltage that powers the unit's relays, thermostat circuit, and contactor coil. The assembly group also covers the companion control relays (P/N 1053004, 24V; P/N 1060940, 24V DPST) used in this model's control sequence. Rated at 40VA, the transformer delivers stable, isolated 24V power to the entire control board and switching circuit. When a transformer fails — usually from a shorted secondary, an overloaded control circuit, or age-related insulation breakdown — the unit goes completely dead on the control side: no fan, no compressor call, and no thermostat response even though line voltage is present. A buzzing transformer, a tripped low-voltage fuse, or 0V on the secondary terminals are the classic failure signatures.

Specifications

Compatibility

Engineered for the Tempstar TEB07R25RTA and shared across the ICP/Tempstar/Heil family of 277V PTAC packaged terminal units that use a 40VA control transformer. Always confirm your unit's primary voltage is 277V before installing — 208/230V models use a different transformer.

Installation Guide

1. Safety First — Disconnect power at the breaker and verify zero voltage with a multimeter at both the line and control terminals.
2. Access — Remove the unit's service panel to expose the control box.
3. Document — Photograph all primary and secondary wiring before disconnecting anything.
4. Remove — Label and disconnect the 277V primary leads and 24V secondary leads, then unbolt the failed transformer from the chassis.
5. Install — Mount the new transformer, reconnect primary to 277V and secondary to the 24V control bus exactly per your photo.
6. Test — Restore power and verify 24V across the secondary and a normal control sequence on a thermostat call.

Signs You Need a Replacement

• No 24V at the secondary terminals while 277V is present on the primary.
• Repeatedly blown low-voltage fuse or no control response at the thermostat.
• Audible buzzing, overheating, or a scorched/melted transformer housing.
• Intermittent control operation that worsens as the transformer heats up.

Shipping & Returns

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