What is this?

Mr_GB

Hi!



What is this big black round thing attached to the boiler?  I'm trying to understand this steam system a bit...



And the 2nd pic, what is the white odd-shaped bulbous thing in the upper left corner?



Last but not least, the boiler is old, nobody knows how old.  The model is a Burnham 408, 613 sq feet of steam as per the label.  Is there a way to find out how old it is?



TIA!

nicholas bonham-carter

that's a "ham"

that is an early air vent, i believe from a vapor system. if you do a search for "ham" here there will be more information. the first bulbous thing in your picture is the low water cut off for your boiler, and it should be blown down weekly to show that it is able to protect your boiler against a low water situation.

i suggest you buy "the lost art of steam heating" at the shop here, and you can learn how to maintain your system.--nbc

Charlie from wmass

The first photo is also

the water feeder for that boiler. It is a combination unit that is a Low Water cut off and an automatic boiler feed valve. The second is indeed a ham, Dan explains that much better than I can in this little box.

Dave in QCA

helpful links

Here is a link to an exploded view of your McDonnell Miller low water cut off and automatic fill device.    http://www.mcdonnellmiller.com/pdf/47_47-2.pdf



Here is a link to a booklet that shows your Dunham air eliminator.  It is on page 61.  Page 62, show the Dunham Return trap, which is commonly known in the trades as "the ham", because of its appearance.

http://www.heatinghelp.com/files/articles/1821/dunham.pdf

TomM

call for boiler age

Last but not least, the boiler is old, nobody knows how old.  The model is a Burnham 408, 613 sq feet of steam as per the label.  Is there a way to find out how old it is?



Call Burnham and give them the serial #.  They'll tell you the manufacture date.  (For future reference:  Tell them you're a contractor if they ask.  Make up a company name.  Sometimes some places won't talk to you if you tell them you're a homeowner.  Some, not all of them. )

kevin_58

age of boiler

My guess would be 1981, due to the date code on the pressure control. It says 80 50 . The pressure control was made in the 50 th week of 1980.

Mr_GB

Wow, interesting info!

Thanks everyone for all this information!  The Dunham catalog was very interesting.  I'm thinking the age of 1980 is probably right, the owner thinks the boiler was installed in '79 or '80 which I dismissed at first.  Guess she might have been right.  Given the boiler is 31 years old, I presume it would be due for replacement soon - how long can these boilers last?  I'm giving some thought to buying the house so I am trying to get a feel for what I'm dealing with.  A 31-year old boiler isn't very inspiring to say the least.



From the pics here, is this a vapor system or just plain 2-pipe steam?  And, what is the difference between vapor and steam heat?  I never saw anything like a vacuum pump on this system.  Just regular traps on rads and the Dunham air eliminator above the boiler.

Dave in QCA

VAPOR

Vapor heat is the term given to steam systems that run at 8 oz of pressure or less.  The Dunham system that used the air eliminator, but no return trap would have fallen into that category.  The check valve that would have originally been on the vent port of the air eliminator allow the air to be vented out, but not drawn back in.  Therefore, while the system did go into a partial vacuum when it cooled off, it was a self-induced vacuum.  No pump was needed.  But, it probably did not get to more than 15 in Hg of vacuum.