Foot Mount Control Class II Transformer 120V / 208V / 240V 90-T40F3 UET105

HVAC/R Foot Mount Control Transformer | Replaces Supco® SXT105

Brand new Supco (SXT105) Class II Foot Mount Control Transformer designed for HVAC/R applications. Replaces multiple OEM transformer models including 4031F, 50354, UET105, 90‑T40F3, AT40A1121, AT40A1139, and AT40B1214. Built for reliable low‑voltage control power in heating, cooling, and refrigeration systems.

This transformer provides stable 24V output for thermostats, relays, gas valves, and control circuits. Includes two 12" leads with 1/4" insulated female quick‑connect terminals for easy installation.

⚙️ Specifications

• Primary Voltage: 120V / 208V / 240V
• Secondary Voltage: 24V
• VA Rating: 40VA
• Mount Type: Foot Mount
• Class II Rated
• No internal breaker or fuse
• Includes two 12" leads with 1/4" insulated female quick connects
• Agency Approval: UR
• Condition: Brand New – Unused

⚠️ Symptoms This Part Fixes

• No 24V output to control circuits
• HVAC system not powering up
• Blown or shorted transformer
• Intermittent control voltage issues

Replaces Part Numbers

4031F
50354
UET105
90‑T40F3
AT40A1121
AT40A1139
AT40B1214
PF42440
SXT105

Replacement For

Jard 4031F
Mars 50354
UEI UET105
White‑Rodgers 90‑T40F3
Honeywell AT40A1121
Honeywell AT40A1139
Honeywell AT40B1214
Packard PF42440

Restore reliable 24V control power with this OEM‑compatible SXT105 Class II transformer — engineered for dependable performance in HVAC/R systems.