Re: Boiiler wash procedure

Understood. But I would add that with square thread plugs, if maintained properly, one should
only need to use a lubricant to aid in application or removal. Having said that maybe there are times when
some additional sealant might be necessary, but when that occurs, one should find out why. Is it
the seat or the plug that is at fault. As you may know, sleeve seats should be a flat 45 degrees while
the plug seat should have a radius.

One area I should have addressed is over tightening washout plugs. Fine thread plugs will end up
being “shouldered”. The steeper the taper, the more easily shouldered. Why shouldered? Over tightened
to keep tight when thread condition is poor.

Square thread plugs can also be over tightened. If your using bronze square or acme thread plugs, be sure
to examine the threads at the thread root for cracking. All bronze Huron and McAvity plugs will show this defect
before the steel thread with copper seat Huron plugs. This was one reason Huron went to Acme thread form
In the late 1940’s in Canada.

I have run into situations where large firebox corner plugs would be tight under pre fire up water test and then
leak when first fired up only to stop leaking after the mud ring finally came up to temperature. This also took place
when using the banked fire overnight when outside practice. A ICC/FRA man thought he had a “good find” only to
find out when I pointed out to wait 10 or 15 minutes that the leak would stop. When leaking you could hold you hand
on the bottom of the mud ring and find it “cold”.

It is also important that the proper materials should used when making new plugs or sleeves.

Chris