Weil McLain 591-391-919 Wiring Harness

The Weil McLain 591-391-919 Wiring Harness is a critical 9-pin interface engineered specifically for Series 4 CGa gas-fired water boilers. As a primary control link, this 9-pin wiring harness establishes secure communication between the control module and essential safety and operational peripherals, including the thermostat, limit switches, pressure switches, and block limit switches. It is explicitly designed for integration with the Honeywell VK8115V-1176 gas valve, utilizing a 19-21 VDC signal path to ensure precise valve modulation and system safety.

For the service technician, this OEM replacement part provides a streamlined plug-and-play installation that minimizes field diagnostics and labor time. The harness features high-grade insulation and robust connectors built to withstand the thermal stresses of the boiler cabinet. Utilizing the 591-391-919 harness ensures that signal transmission for temperature control and fuel consumption remains accurate, preserving the operational integrity of Weil McLain heating systems without the compatibility risks associated with universal aftermarket wiring.

• Precise Compatibility: Specifically designed for Series 4 CGa boilers utilizing the Honeywell VK8115V-1176 gas valve.
• Optimized Signal Integrity: Ensures reliable 19-21 VDC transmission between the control module and safety limits.
• Efficient Field Service: Simplifies repairs with a direct-fit 9-pin connector setup, reducing downtime for the end user.
• Durable Construction: Engineered with materials rated for high-temperature HVAC environments to prevent circuit failure.

• Is this harness compatible with all Weil McLain CGa boilers? No, the 591-391-919 is specifically for Series 4 units. Always verify your boiler series and gas valve model (VK8115V-1176) before installation.
• Does this include the circulator harness? This specific part number is the 9-pin control harness; circulator harnesses are typically separate assemblies depending on the specific boiler configuration.
• What does the 9-pin interface control? It manages the logic loop between the module, thermostat, and various safety switches like the pressure and block limit switches.

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.