Problem with bottom blow down drain

DRod_3

My approx. 30 year old Weil McLain single pipe steam boiler works pretty well. Original was likely coal fueled, this one is natural gas.  Several years ago, The Wall helped me get it into shape.  Now, a new issue:  The bottom drain outlet (regular gate valve) doesn't open, so I can't drain the dirt / crud from the bottom of the boiler.  I can turn the handle, but nothing opens up and nothing flows out.  Should I attempt to repair the gate valve?  How?  Or...Should I replace it with a new duplicate or with a ball valve?  Any suggestions and precautions would be greatly appreciated.  Thanks. 

gerry gill

Replace it.

I would use a full port ball valve in that application.

DRod_3

Thanks, more questions

Thanks.  Should I use two pipe wrenches?  One for holding the furnace fitting in place and one for removing the valve? 

Any special precautions? 

I assume the furnace should be shut down for a few hours to cool.  Do I have to turn off the pilot in case I end up draining the boiler? 

gerry gill

shut it down and let it cool a bit..

the pilot shouldn't really be a concern unless its one of the big honkin jobbers..yes, always use a back up wrench, but be prepared to change the nipple into the boiler..chances are good you will end up doing just that.

DRod_3

Set up at bottom drain

Thanks again.  My Weil McLain unit looks like the one you posted here.  On my unit the bottom drain is off the black pipe drop down at the bottom of the equalizer loop.  The pipe from the boiler drops down and out with a couple fittings.  The valve is screwed directly into the black pipe---the last part of the drop down add on.  Looks pretty straightforward for removal, but looks can be deceiving, I've learned.  I'll put the first wrench onto the black pipe/fitment adjacent to the valve. 

Sound okay?