Very Old System

Melee

I have a very old 1936 oil boiler steam system and it has not been run since 1996. The building is 8400 sf and I need to put a new boiler in.

I would like to put a direct vent or condensing system in fueled by gas. 

I have been looking at boilers and am confused as which one is the best for the job. Please can you recommend some models that will work for this application and or a better way to go with such a system.

Also I am looking for a steam guy in the Boston Area.

Jamie Hall

Very old?

1936 isn't that old... although it is for the boiler.



Problem: direct vent and condensing boilers are only for hot water heat, not steam.  However ot to worry;there are a number of very good gas fired steam boilers made which will do the job for you -- and the difference in real running efficiency between them and the mod-cons is insignificant, in my humble opinion.



I wouldn't want to recommend a specific make or model without knowing what the heat requirement was.  Fortunately, that isn't that hard to figure out for steam: you add up the effective radiating area, called EDR, of all the radiators which will be served, and that determines the size.



You do well to look for a good steam man(or woman)  to do the work, though.  Have you tried "Find a Contractor" on this site?  Search by State, though, not zip code.

nicholas bonham-carter

very old boiler

when you mention direct vent are you requiring an alternative flue option instead of the pre-existing chimney? there are some which can be used with a power vent, but the best solution is to reuse the original chimney, with any repairs/relining it may need.

certainly as jaimie says, the sizing of the new boiler is done by calculating the total radiation, not by heat loss, or previous boiler capacity. you may likely find that the previous boiler was grossly oversized, and has been very wasteful over the years as a result.--nbc

Melee

Very old boiler

Thank you both for getting back to me. So what I am reading about steam condensing boilers is not exactly true and they don't work well for steam.



The existing chimney is being removed and the heating needs to be vented differently. I am planning to do the EDR tomorrow to figure out the boiler size. Yes the old boiler is huge 10 feet long by 6 foot high.



If you would share 2 or 3 brands of boilers I can then research them to see what will work best.

crash2009

Sizing chart and boiler piping video

Here is the boiler sizing chart.  It shows various types of radiators and how to arrive at their EDR.  Also since you are starting from scratch you might want to watch this video and maybe keep it handy for down the road.  http://www.heatinghelp.com/article/107/Steam-Heating/118/Steam-boiler-near-boiler-piping

Jamie Hall

Boilers...

Ah.  Well, direct vent steam is available.  But as I noted, condensing isn't -- but you don't need it.



Makes?  Burnham, Slant Fin, Weil-McClain... there are more; look around various posts and you'll see them mentioned.  Keep in mind, though, that unless you plan to do it yourself you are buying the installer as much as you are buying the boiler; a good installer can make pretty much any boiler sing, but will prefer one or another brand.  A bad installer can make a mess out of the best boilers made.

nicholas bonham-carter

Alternative flue arrangement

Maybe the new flue pipe can follow the route of the old chimney up through the roof. A new flue would probably give additional economy as the gases are not traveling into an over-sized (for coal) chimney, with a huge amount of excess air.

Will this boiler also make hot water?--nbc

Melee

EDR

Ok I measured all 42 radiators and have come up with 1619 EDR but now I am confused on the work sheet you have x 250 = 404,750 BTU.



I thought it was 1.33 then  250. = 538,317 BTU (to include piping)



Also you have a width measurement on your work sheet that I did not take into account. (I am using Dan's book Greening Steam) Plus I have wall mounts so I am going to take your chart and redo my math.



The Burnham Independence PV direct vent reads well do you have any knowledge of this system and if it works well.



I believe I have a great steam guy I just want to make sure we are both on the same page.

Melee

Good Plan

Yes the chimney is huge and is going to house all the electrical runs to the roof. That is why I have been looking at direct vent. But this may just work.

crash2009

I think that's it

Once you get to total EDR of radiators (1619) go boiler shopping.  The 1.33 is all ready built in to the boiler.  You don't even need the X 240 at this point. 

Melee

EDR

OK I have been looking at the specks and can not find the EDR??? Where do they hide this?

I am feeling pretty stupid at this point...

crash2009

I'm sorry, you were on the right track yesterday

I thought they figured it out for you.  I thought it was part of the literature.  I know how to figure out mine.  My D.O.E. Heating capacity is 163,000.  163,000 divided by 1.33 equals 122,556.  122,556 divided by 240 equals 510.  510 is the amount of EDR that this boiler should have connected to it.



To figure yours we would start with 1619 multiplyed by 240 to get 388,560.  Then 388,560 multiplyed by 1.33 to get 516,784.  You would be looking for a boiler with a D.O.E. Heating Capacity of 516,784.  Also known as 516,784 btu/hr.  Might also be shown as 516 MBH



There must be a shortcut, this is a pain in the neck:)

crash2009

Have a look at Daves water content chart

http://www.heatinghelp.com/forum-thread/140141/Boiler-Water-Content-Comparisons



Daves chart has the boiler size listed as Gross Output.  This chart might be helpful to you so you can get familiar with the various manufacturers and how they name their various boilers.  Weil Mclain 580 looks close to the size you might need.



http://www.heatinghelp.com/files/posts/11794/WATER%20CONTENT%20OF%20VARIOUS%20BOILERS.pdf