Weil McLain 511-246-330 Gas Valve
The Weil McLain 511-246-330 Manual Main Shut-Off Gas Valve is the OEM 1-1/4-inch NPT manual gas valve with a 1/8-inch NPT downstream pressure tapping, used at the head of the gas train on Weil-McLain gas boilers. Weil-McLain's LGB-6 to LGB-20 Series 2 control supplement parts list shows it as the 1-1/4-inch Kinco-Balon 600, with the 1-inch Kinco-Balon 500 listed beside it as the 511-246-325. The factory photo shows the cast 600 mark on the body, the c-CSA-us certification mark, a flat lever handle on a domed stem, wrench flats on both pipe ends and a side tapping with a screw plug.
A manual main shut-off valve is the service isolation point for the boiler gas train. It lets a technician close the gas supply before working on the gas valve, regulator, pressure switches or burner, and it gives the installer a safe, accessible way to shut the boiler down in an emergency. The 1/8-inch NPT downstream tapping is the gauge port: with the valve open and the boiler firing, a manometer connected there shows the gas pressure reaching the gas valve, which is the first reading you take when diagnosing ignition lockouts, low flame or pressure switch trips.
Over the years a lever valve can fail in recognizable ways: a handle that will not turn, gas seeping around the stem, leakage at the pipe threads or a valve that no longer shuts off fully. Do not tolerate any of them on a gas appliance. The 511-246-330 belongs to a family of Weil-McLain shut-off valves, so keep the sizes straight: the 511-246-305 is the 2-inch valve, the 511-246-325 is the 1-inch valve and the 511-246-330 is the 1-1/4-inch valve, and the 511-246-340 and 511-246-345 are pilot-line valves. The 511-246-330 is a manual main shut-off; the factory Honeywell gas valves listed beside it in the same parts list are separate parts. To replace it, shut off the gas upstream, purge and secure the line, match the pipe size, use approved pipe sealant on the male threads, orient the handle and flow direction as the old valve was installed, then leak-test every joint with a bubble solution and check the downstream pressure at the tapping before putting the boiler back in service. This is work for a licensed gas technician.
Key Benefits
- 1-1/4-inch NPT shut-off: The 1-1/4-inch Kinco-Balon 600 manual shut-off valve in the Weil-McLain LGB control supplement parts list.
- Built-in pressure tapping: A 1/8-inch NPT downstream port gives you a gauge connection for gas pressure checks without adding a fitting.
- OEM Weil-McLain number: The factory 511-246-330, so you match the old valve by part number instead of guessing by size.
- Positive manual isolation: A lever handle gives a clear open or closed indication for service and safety shutdown.
Common Questions
What size is the Weil McLain 511-246-330?
It is a 1-1/4-inch NPT manual main shut-off gas valve with a 1/8-inch NPT downstream pressure tapping. The 511-246-325 is the 1-inch version and the 511-246-305 is the 2-inch version.
What is the 1/8-inch tapping for?
It is the downstream pressure port. Connect a manometer there to read gas pressure at the gas train while the boiler fires.
When should the valve be replaced?
Replace it if the handle is seized, if there is gas leakage at the stem or threads, or if it no longer shuts off fully. Leak-test all joints after installation.
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.