Wayyyy oversized steam boiler

tim smith

Looked at a job yesterday that has a tad oversized steam boiler. One of the largest commercial mechanical co. in Seattle put it in for this client back 10 or 15 yrs ago, owner of mech co new the client so made them a (deal). I think it was left over from a no go job. This is one of the high end communities in Seattle. Both client and owner live in the same community. House appx 4000 ft, 1920s construction. Boiler is 900,000 input!!!!! I have not done radiator count yet but WOW. I suspect load will be max of appx 200mbh. Talking about short cycling. Will be interesting if we can get them to replace for proper size boiler, we are doing other work on site so will discuss with them. Tim

ttekushan_3

neighborly.

Don't replace it- See if the neighbors need steam piped into their homes for heating. A nice little three house district heating system. They could make $ off this! Don't know why I never thought of it before.










Maybe because its just silly. But still......

nicholas bonham-carter

oversized boiler

would a hi-lo burner make this situation better?
the district heating solution sounds interesting, but think of the condensate return problem!--nbc

Arnold

way oversized system

I have a newly installed one pipe system in a 4 floor apartment building (4 apts). Total floor area approx. 4200 sq ft. Building has 40 (yes forty!) windows Radiators are new slenderized type sized to closely match assumed heat loss. Gas boiler input 160,000 btu. 420 sq.ft EDR. All floors seem to heat adequately. This is my first heating season and I am nervously awaiting the real winter to see if all the principles discussed here on the wall really work. Maybe I do need that 900,000 btu boiler instead? What do you pros think? Am I too optimistic? Go easy on me, guys. I am just a committed landlord who knows a little too much for his own good.

tim smith

It's atmospheric, no go on low hi low

nicholas bonham-carter

atmospheric hi-lo

peerless for one ofer a modulating gas valve setup for their atmospheric burners,called the "mod-u-pack",probably other mfgs. as well.

http://forums.invision.net/Thread.cfm?CFApp=2&&Message_ID=421691&_#Message421691

i presume its mixture of gas and air is going to be incorrect on one of the stages of firing, but isn't that still better than an over sized boiler?--nbc

nicholas bonham-carter

apt bldg.

if the total radiator load was correctly calculated to match the boiler capacity, you should be all right. it might be difficult to just put in a bigger boiler, without also putting in more radiators.
with radiators of lower thermal mass it becomes even more important to vent the mains as quickly as possible so that steam arrives asap when the boiler control calls for heat.what sort of control will you use here?
if the occupants are cold, just tighten up the envelope.if you will need a new roof soon, you can add 2-4 inches of foam underneath the new roof [i like pvc instead of rubber-remember flat tires?]good luck.--nbc

tim smith

I would say no on this older cast iron atmospheric boiler for

low high low. On low fire the air entrainment would not be good enough for stable combustion on these old cast iron burners. Would be a problem most likely. Tim