M&J Valve Gate Valve M-303

Ensure replacement seat rings are available before disassembling the valve.

Verify valve is not exposed to line pressure.

Isolate pressure source from pipeline and valve.

Cycle the valve to the mid travel position.

Open the valve body pressure relief valve to vent trapped body/line pressure.

Remove bonnet nuts and studs for work clearance.

Lift the entire top works assembly, bonnet, and gate to clear the T-bar slot in the gate neck.

Inspect, clean, and lubricate the valve components

Run the valve through a full cycle if field conditions allow

Ensure replacement stem is available

Ensure stem packing and O-rings are available for replacement

Verify valve serial number for correspondence with M&J Valve

Is the pressure source isolated from the pipeline and valve?

Cycle the valve to the mid travel position

Open body pressure relief valve to vent trapped body/line pressure

Cycle the valve to the full open position

Ensure replacement stem is available

Ensure replacement stem packing and O-rings are available

Include valve serial number in correspondence with M&J Valve

Isolate pressure source from the pipeline and valve

Cycle the valve to the mid travel position

Open valve body pressure relief valve to vent trapped body/line pressure

Cycle the valve to the full open position after venting is complete

Pre-maintenance Cautions and Preparations

Ensure no stem maintenance on valves with cupola while exposed to line pressure.

Verify replacement stem, stem packing, and o-rings are available.

Record valve serial number for correspondence with M&J Valve.

Isolate pressure source from pipeline and valve.

Cycle the valve to the mid travel position to allow venting.

Open the valve body pressure relief valve to vent trapped pressure.

Cycle valve to the full open position after venting is complete.