Weil McLain 383-500-195 Transformer

The Weil-McLain 383-500-195 Transformer is a critical OEM component designed to step down 120V line voltage to 24V control voltage for high-efficiency hydronic systems. Engineered specifically for the Weil-McLain Ultra Gas Boiler series (including Series 1, 2, 3, and 4), this 50VA rated transformer provides the stable power required for the U-Control module, gas valves, and safety limit circuits. Its precision windings ensure consistent secondary output, preventing the "nuisance trips" or control board brownouts often associated with generic aftermarket alternatives.

For service technicians, this unit is a direct-fit replacement that maintains the integrity of the original HVAC wiring diagram. It is built to handle the inductive loads of circulator relays and ignition controls common in condensing water boilers like the Ultra-105 or Ultra-155. When diagnosing a dead control interface or a flickering 3.5-inch LCD display, verifying the 24VAC output at the secondary terminals is a standard field procedure. This genuine part ensures the boiler control module receives "clean" power to manage outdoor reset functions and domestic hot water priority without interference.

• OEM Compatibility: Exact replacement for the Weil-McLain 383-500-195, ensuring bolt-on installation and correct lead lengths.
• System Stability: Specifically rated at 50VA to support the complex power requirements of Ultra boiler control logic.
• Reliable Stepping: Efficiently converts 120V to 24V to power sensitive thermostat circuits and multi-zone relays.
• Durable Construction: Built to withstand the thermal cycling and vibration found within high-performance sealed combustion chambers.

Is this transformer compatible with other Weil-McLain models like the CGi or GV?

While primarily specified for the Ultra Gas Boiler series, compatibility depends on the VA rating and mounting footprint. Always cross-reference your specific model's parts list to confirm this part number is the approved boiler repair part.

What causes an HVAC transformer to fail prematurely?

Failure is typically caused by a short circuit in the low-voltage field wiring, such as a contactor coil burn-out or a wire grounded by an external fastener. Professionals should always clear the short before energizing the new 120V/24V transformer.

How can I verify if my current transformer is bad?

Using a multimeter, check for 120V at the primary input. If primary power is present but there is no 24V reading at the secondary output (and no tripped in-line fuse), the internal windings are likely open, necessitating a replacement.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.