Dry steam vs. velocity

mel rowe

A few days back you gave me some good info on steam velocity. If you recall, I had added a second 2 in. taping to my 299,000 btu boiler and reduced the velocity by half, to about 27 ft./sec. With my 32 inch risers to the 3 in. header, do you think this would be good, or not? You said you liked to have it in the 16 ft./sec. range. With only two 2 in. tappings available on my boiler, I am at a loss as to how to lower velocity further.

Unknown

tfi-everhot makes an anti-surge tank that reduces the exit velocity. Unfortunately they dont have the product on their website. I cant locate any literature on the product, but your local supplier may be able to furnish some.

Steamhead (in transit)

You won't be able to reduce exit velocity

but the 3-inch header should slow the steam down to where the system can handle it.

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mel rowe

Thanks for the replies. It's frustrating that boiler mfgrs.( Utica in my case ) don't even give you a chance to achieve desired steam velocity, since there are only two 2 in. tappings available. For a large residential boiler like mine I wonder why they wouldn't provide two 3 in. tappings?Imagine what kind of steam was being fired through my system before I installed the second tapping and the 3 in. dropped header. And the installation manual showed the second tapping as optional. Unbelievable.

Unknown

all of the Weil Mclain

All of the weil mclain gas eg and egh boilers have TWO 3" top tappings and can do what you want to do with it...

Ken_40

Which is precisely

why we feel W/M is a standout manufacturer of steam boilers!

A johnny homeowner boiler with two 3" riser pipe outlets?

Killer design/engineering IMHO

John N

Most low-water content boilers are built with sections cast too narrow (W-M is an exception) to accept any but 2" tappings. That's why the near-boiler piping is so crucial. It takes the place of the large steam chest and tappings of the old boilers. It's odd that Utica Boilers would say that use of the second tapping is "optional". The ECM website has some info under "Utica Radiator Ratings", which shows on the second page recommended near-boiler piping. It says, (in bold print) "Both 2" supply tappings must be used. All near-boiler supply header piping must be a minimum of 2". Do not reduce". It also gives recommended header sizes for the different size boilers ranging from a 3-section boiler (2") to a 5-section boiler (3").

John N

Most low-water content boilers are built with sections cast too narrow (W-M is an exception) to accept anything wider than 2" tappings. That's why the near-boiler piping is so crucial. It takes the place of the large steam chest and tappings of the old boilers. It's odd that Utica Boilers would say that use of the second tapping is "optional". The ECM website has some info under "Utica Radiator Ratings", which shows on the second page recommended near-boiler piping. It says, (in bold print) "Both 2-inch supply tappings must be used. All near-boiler supply header piping must be a minimum of 2-inch. Do not reduce". It also gives recommended header sizes for the different size boilers ranging from a 3-section boiler (2") to a 5-section boiler (3").

mel rowe

When my replacement boiler was installed 17 years ago, the installation manual, which I still have, showed the second tapping as optional. Maybe Utica learned from the Wallies and Dan's books that two tappings were a necessity ( but still not enough to achieve desired velocity ). LOL I know that's how I found out and installed the second tapping and a 3 in. header to try and improve the system.

John N

Somewhere around here I've got a manual from a 5200 installed in '92. I'll have to look at it. I can't imagine Utica giving information like that! In any event, all modern boilers, by virtue of their low-water content, cannot produce the low velocity steam necessary for good operation without proper near-boiler piping. The large headers are intended to slow the steam velocity down for good operation.

mel rowe

My Utica boiler was a Series Peg-A, rated at 299,999 btu input. Anyway, it sounds like the Weill-McLain boilers with two 3 in. tappings can achieve the desired max. velocity. Apparently other boilers with only 2 in. tappings cannot.

Steamhead (in transit)

I think they changed that

because they had trouble with tilting water lines which sometimes caused sections to crack. I've changed out a bunch that had only one steam tapping hooked up, but never one that had them both hooked up.

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