Tempstar 40VA Transformer for TEB09R25RTA — 277V to 24V with Relays | Ships Today

Overview

This OEM control package for the Tempstar TEB09R25RTA PTAC unit centers on a 40VA step-down transformer (part 1091226) that converts 277V line power down to the 24V needed by the control circuit, paired with a 24V relay (1053004) and a 24V DPST relay (1060940). The transformer is the heart of the low-voltage system — every relay, thermostat, and contactor depends on its clean 24V output. When a transformer fails (shorted winding, open primary, or blown internal fuse), the entire unit goes dead with no control response. The DPST and SPST relays handle the switching loads the transformer powers.

Specifications

Compatibility

Direct OEM fit for the Tempstar (ICP / Heil) TEB09R25RTA 277V PTAC model. Confirm your line voltage is 277V before ordering — this transformer is not interchangeable with 208/230V control transformers.

Installation Guide

1. Safety First — Disconnect the 277V supply at the breaker and verify zero voltage at the primary leads with a multimeter.
2. Access — Remove the front grille and control-box service panel.
3. Document — Photograph all primary and secondary wiring and relay terminals before disconnecting.
4. Remove — Unbolt the transformer from its bracket and release the relays from their clips, labeling each lead.
5. Install — Mount the new 40VA transformer and relays, then reconnect every wire exactly per your photos.
6. Test — Restore power and confirm 24V on the secondary and proper relay pull-in.

Signs You Need a Replacement

• Entire unit dead with no control response
• No 24V reading on the transformer secondary
• Repeated control-fuse failures or a burnt transformer smell
• Relays that won't pull in or chatter under load

Shipping & Returns

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