ASME Boilers

Yanche wrote:

coaledsweat wrote:Once tripped, a lot of them will drip. Some eventually stop, some do not. It gets worse with steam.

My approach to the dripping after testing is to make it easy to replace. I install them with a full port ball valve. Then when one continues to drip after testing it's easily removed. I just reuse the cleaned or refurbished one from last year's removal that continued to drip. Almost always, only the gasket or seat needs cleaning. To assure the ball valve doesn't get closed I remove the handle or wire and tag it in the open position.

I once proposed this valve idea to a mentor - who just about spit his coffee at me and in short four letter words with other gyration and experlative "suggested" that if I ever did that on one of his jobs, and the boiler inspector didn't have us killed --- He would!

I suppose bad experience can be a harsh teacher. Your mileage may vary.

Don't see the problem if you use it for changing it, I see the plumbers/inspectors point of view too. I could see homeowners simply shutting the valve off to "fix" it.

Sting wrote:

Yanche wrote:My approach to the dripping after testing is to make it easy to replace. I install them with a full port ball valve. Then when one continues to drip after testing it's easily removed. I just reuse the cleaned or refurbished one from last year's removal that continued to drip. Almost always, only the gasket or seat needs cleaning. To assure the ball valve doesn't get closed I remove the handle or wire and tag it in the open position.

I once proposed this valve idea to a mentor - who just about spit his coffee at me and in short four letter words with other gyration and experlative "suggested" that if I ever did that on one of his jobs, and the boiler inspector didn't have us killed --- He would!

I suppose bad experience can be a harsh teacher. Your mileage may vary.

I too had reservations about the valve, but was assured by the plumbing professionals I asked that "service valves" with appropriate tags were allowed. Now I have to admit I've not seen it written in a code book and the individuals I consulted are not residential plumbers but industrial process experts.

Yanche wrote:I too had reservations about the valve. Now I have to admit I've not seen it written in a code book and the individuals I consulted are not residential plumbers but industrial process experts.

I would think it OK on a hot water boiler, providing the valve is lockable. I would also say an absolute no-no with steam. We make it a habit not to work anywhere on the pressure vessel as long as it is under pressure.

As far as the PRVs go, you can't trust them. My steam boiler at work has a pair of two inch safeties. They are replaced yearly when Factory Mutual does the internal inspection with another pair that are cleaned, calibrated and tested. They come certified with a nice tag for the inspector. One year with the fireside opened, I decided to fill it with water and run the feed pump to look for any internal leaks because the Kaowool gasket at the rear door would drip water at startup (I thought I had one but it was condensation). It ran up to 210-220# and neither of the just installed safeties popped even though they were set @ 150#. The inspector wasn't surprised by it at all.
The inspector also comes around about 6 months later and does a walk around while it is running and at pressure. He will often ask me if I test the safety valves and I say no. I then ask him if he would like me to do so for him and he says no.

By the way, if it is leaking, you could try exercising it a few times. It is usually just crap on the valve seat causing them to leak. My oil burner's drips on occasion, I can live with the dot on the floor.

I operate two steam turbines that turn vacuum pumps. You should pop off a 175 lb relief two feet from you. If you aren't ready for it, you'll need to change your drawers.

cArNaGe wrote:I operate two steam turbines that turn vacuum pumps. You should pop off a 175 lb relief two feet from you. If you aren't ready for it, you'll need to change your drawers.

I had mine re piped, the PRV vents go up through the roof now.

vtec: which town are you from, if you don't mind my asking? I'm in the same shoes and trying to figure out the way to get our local inspector to OK Keystroker unit I was eying.

[quote="coaledsweat"]
I would think it OK on a hot water boiler, providing the valve is lockable. I would also say an absolute no-no with steam. We make it a habit not to work anywhere on the pressure vessel as long as it is under pressure. [quote]

If the valve is closed on a hot water system, it will be a steam system just before "La-BOOM".

You can't make steam without a headspace Freddy, the hot water could flash to steam after the "La-BOOM" though.

One quarter of a micro second after the boiler splits you'll have all the headroom you need to make steam! The flash, steam and boom will all happen with a micro second or two. Did you see the Mythbuster show when they heated a hot water tank until it blew? Very impressive.

Yup, I saw it. But a full hot water boiler won't go boom if it splits, the pressure would be gone at the first rupture. A steam boiler is another story. This is why you should always fill a vessel completly with water before a pressure test (hydronic). The water cannot be compressed and at first rupture the pressure it does build is lost instantly, not so with air or steam which can be compressed considerably. It's the compression that brings the danger.

"a full hot water boiler won't go boom if it splits"

I beg to differ. The Mythbusters tank was full of water. It's not the compression that brings the danger, it's the super heated water turning to steam and suddenly taking up thousands of times the space.

"it's the super heated water turning to steam and suddenly taking up thousands of times the space."

Exactly, Water under pressure has a higher boiling point. As soon as you release that pressure the water will boil and turn to steam. It's that inatant transformation that will cause the BOOM.

Terry