WM egh steam boiler -- sight glass drain valve question

jlt83

I am looking to install a sight glass drain valve on my Weil-McLain EGH steam boiler. The bottom valve seems to have a drain plug. I have two questions:

1) If I close both valves and remove the plug, will only the water in the glass spill out? Or will the boiler empty into my lap?

2) What size valve will fit into the plug? Is there a special type/brand that I should look for?

Thank you

EBEBRATT-Ed

If you close both valves only the water in the glass will drain.

I think the threads are 1/8" ips but I am not positive.

@gordo & @Steamhead have a valve they like to use. They will probably respond. Or search on You tube "Silent Steam Team"