Old WM boiler

Ken_40

The "Series 3" simply means there were at least three minor changes to that model; you having the third variation of the original model. The "B" in W/M model nomenclature means it did not necessaily have a factory installed burner, just the "B" boiler. (Not a "P" as in packaged - with burner) - There are many exceptions to this, so beware of assuming too much.

The actual model is based on the number of sections that 'makes' the boiler complete. If it has one front, one back and one intermediate section, it is known as a '3' as in B-357. If it had two intermediate sections, it would be a B-457. Since all sectional boilers always have a front and a back section, the minimum is a "2" - which there are a few of!

Hope you're not completely confused now (;-o)

It is always possible to "under-fire" a boiler, frequently to some advantage. One should NEVER over-fire a boiler, however. The dangers are numerous and can be deadly.

mel rowe

Just today I ran across an old Weill McLain oil fired boiler that was converted to gas. Until I get it cleaned up a bit and get a better light the only thing I could make out on the plate was No. 57. Can anybody shed any light on its vintage and capacity and what kind of efficiency might be expected at this point?

[Deleted User]

My 57 literature

is dated 1962. Gross is 72% of rated input. 4 sizes.
Oil inputs 1.20, 1.55, 1.90, & 2.20 GPH.

Unknown

Does this help mel?



Dave

mel rowe

Thanks very much for the info. Maybe with this I can figure out very faint numbers I see on the boiler.

mel rowe

Got a closer and better look at the old boiler. It is marked as a series 3, so I guess from Dave's info that makes it a B-357. This would be a 194,000 btu input boiler, with a output rating of 145,500. This is confusing because the replacement burner (gas) says 135,000 max./hr. The boiler isn't set up very well, and it hasn't been maintained very well, either,so I think the age, efficiency and condition probably mean a replacement is in order. I'm going to start calculating the radiator EDR and evaluate boiler capacity requirements.

Steamhead (in transit)

Complicating the issue

is the fact that there were two W-M boiler types that were called the 57 series, according to the Hydronic Rating Handbook.

The first was designed for coal firing. This 3-57 had Net ratings of 435 square feet of steam, 103.8 MBH on hot water when hand-fired.

But I suspect you have the second 57 series, which was designed for oil firing and had prefix letters such as A, B, K and O. It had a round plate for a tankless coil in the upper right corner of the front, and a large square plate on which the burner was mounted. This one had Net ratings of 605 square feet steam, 145.5 MBH hot-water and its firing rate with a non-flame-retention burner was 1.9 GPH. With a high-speed flame-retention burner you'd get the same heat input with 1.5 GPH.

The later 57 appears to be a vertical-flue type. If it has a high-speed flame-retention burner and a Kaowool chamber you could probably get 80% out of it.

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mel rowe

Thanks Ken and Steamhead. Looks like I have more detective work to do.