replacing one 750 mbh steam boiler with multiple (3) boilers

charlie_6

A coustomer has requested we quote a series of staged multiple steam boilers to replace one older steam boiler. There is a lot of pipen in the old system and I wonder if pick-up loss ,low steam volume, and control issues will make this a problem job. Any thoughts? If it were hot water I would be less anxious about it.

Unknown

It's done all of the time successfully

Multiple boilers, or modular boilers, the chief difference being the controls and valving.

Modular boilers are considered all one boiler, by the manufacturer, and have the manual reset pressure control, and the manual reset LWCO kill the whole bank of modules; and there are NO VALVES BETWEEN ANY MODULE AND THE MANUAL RESET CONTROLS ON THE COMMON PIPING.

Multiple boiler systems have each boiler module controlled with it's own set of controls, and valves are permitted between modules, and is also acceptable. It's more expensive.

The manufacturer will most likely send you a piping, wiring, and venting diagram, whichever way you go. (I will if you chose our system).

Check here...

http://www.slantfin.com/prod-caravan.html

Noel Murdough

Slant/Fin Corp.

800 873 4346

Blackoakbob

Where'd the water go

Charlie,
as important as the boilers and the control package is the
feedwater (condensate return) pumping and holding capacity.
Chances are the old boiler holds many gallons of water, at or near steaming temperature and when you replace it with those modules, holding only a few gallons each, you'll need someplace to hold the condensate as it returns and pumps to feed the boilers as they steam up. A large capacity condensate tank and a dedicated feed pump to each module works well, operated from a M&M control or the like.
Sounds like a fun job! Good Luck.

Robert O'Connor_7

Boiler(s)?

The existing seems a bit small to go through all that. I've done it, but its ALOT of work, but hey if the $$ is right go for it...Robert O'Connor/NJ

Unknown

Before you guys sell all of that equipment,

and decide that it's too expensive to do, I'd like to ask a couple questions.

Why did you suggest condensate tanks, or boiler feed tanks? Is there a problem with the system that these tanks will solve?

What is the load on the new boilers? How did you decide what size system this is? From the old boiler, perhaps? Do you know what the load will be after the piping warms up, and two boilers, perhaps, can cary the load, saving 1/3 of the fuel (only during the run time) while running longer, more efficient cycles (the true benefit)?

Will insulating any of the system make sense? Venting? Cleaning returns?

My gentle point is this: I wouldn't suggest to someone on the internet that is looking for information, that they NEED a whole mess of equipment, and that they can't afford it. Just do what the last guy did.

There ARE options.

Noel

Boilerpro_3

I'm with Noel

I haven't done any steam modulars, yet, but I have found that any time a peak design space heating load is over about 160,000 btu/hr, stage fired multiple boilers are the way to go becausethey pay back their increased installed costs with lower fueling costs. I would expect the savings would be even greater for steam due to the large amount of extra boiler capacity often needed to just get the system up to temp and then most of this pick up load drops out. You end up with way too much boiler nearly the whole heating season. Of course if you have zoned steam, then the modular/mulitple route looks even more attractive in terms of potential fuel savings.

Remember a 750,00 btu/hr pead load space heating system (which would heat about a 40,000 sq ft 1910 church facility for instance)will cost about $10,000.00 to $15,000.00 per year in fuel. If you save only 10 to 15 % of this amount by going to modular/multiple stage firing, you are saving roughtly $1,500.00 per year in fuel.... that pays for the extra up front costs pretty quick...alot quicker than investing in stock.

Boilerpro