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This genuine OEM control transformer (part #1173691) with terminal barrier (part #1178431) supplies low-voltage control power for the ICP/Tempstar/Heil WPG4484090RKA1 packaged unit. It steps the 208/230V line-voltage primary down to a 24V secondary rated at 40VA, powering the control board, contactor coil, gas valve, and thermostat circuit. When a transformer fails — usually from a control-circuit short, a shorted gas valve, or simple age — the entire 24V system goes dead: no thermostat display, no contactor pull-in, and no ignition. A transformer that buzzes loudly, runs hot, or has a blown internal winding must be replaced to restore control power. Always correct the short that caused the failure before installing a new transformer.
| Spec | Value |
|---|---|
| Part Numbers | 1173691, 1178431 |
| Type | Step-Down Control Transformer |
| Brand | ICP / Tempstar / Heil |
| Primary Voltage | 208/230 VAC |
| Secondary Voltage | 24 VAC |
| Rating | 40 VA |
| Fits Model | WPG4484090RKA1 |
Factory replacement for the ICP, Tempstar, Heil, and Comfortmaker WPG4484090RKA1 packaged unit. Confirm the primary tap voltage (208 vs 230), 24V secondary, and 40VA rating against your existing transformer before installing. The included barrier (1178431) protects the secondary terminals.
Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.