How to Stop Check a Boiler Valve

Indicators on stop check valves can be seen from floor level.

Boilers are designed with many safety features, including stop check valves. These valves are designed to shut off the boiler from the rest of the system in the event of accident or to allow for repair work on the line. They are not meant to control the flow of steam and pressure, but to cut it off or release it into the system. In other words, they allow the operator to stop the pressure flow and check the system. When it is time to stop check a boiler valve, no special tools are needed, but you should always exercise caution when working near a boiler.

Things You'll Need

• Work gloves
• Safety glasses
• Ladder (if needed)

Instructions

1. Put on a pair of heavy work gloves and safety glasses.

2. Locate the stop check valve on the boiler. Stop check valves are installed vertically on the top of the boiler. The valve will be in a vertical position and will have a highly visible indicator pin colored orange or red. The indicator pin should be near the top of the valve and should show that the stop check valve is open.

3. Climb up to the level of the stop check valve. Use the ladder attached to the boiler for this purpose or set up a ladder in order to reach the valve. If setting up a ladder, have a helper hold it steady while the stop check is being performed.

4. Grab the handwheel with both hands and turn it counter-clockwise until the indicator pin is at the bottom of the threaded rod and the wheel will turn no further to close the valve.

5. Perform the necessary work on the system. When finished with the work, climb up to the stop valve and turn the handwheel clockwise until the indicator pin is at the top of the threaded rod to open the stop check valve.

Tips & Warnings

• Open and close the stop check valve on a regular schedule to keep the valve in good working order. If the valve is left open or closed for too long, corrosion could build up and freeze the valve.

• The stop check valve must be completely closed before work is done on the system or pressure and steam will still be present in the lines, increasing the risk of serious injury.

References

• Davis Valve: Boiler Stop Check Valves
• Spirax Sarco: Boiler Fittings and Mountings

Resources

• P.C. Mackenzie: Boiler Maintenance Tips