Weil McLain No. 57 Series Boilers

WMno57

@bdugan and I both have WM 57 series boilers. Mine is Boiler Number (model number?) AB-257. We both have questions about these vintage boilers. How old, how efficient, what modern burners are a good fit, etc.

Thanks!

STEVEusaPA

WMno57 said:

@bdugan and I both have WM 57 series boilers. Mine is Boiler Number (model number?) AB-257. We both have questions about these vintage boilers. How old, how efficient, what modern burners are a good fit, etc.

Thanks!

Very old
Not very. Probably overall efficiency maybe 50%
Why bother? Put the money into a new one

WMno57

STEVEusaPA said:

Why bother? Put the money into a new one

I might. I will make that decision with math. Not with guessing. Not with "environmental guilt". Not with "all the cool kids have a mod-con, so I should get one to".

Kind of like the process you would use (I hope) to size a boiler.

bdugan

Me too: I would not rule out replacing this furnace at all, but I do want to understand it as well as I can first.

@WMno57, what is the range on the gauge on yours, and what kind of pressures do you usually see it running at? (If you don't mind me asking!)

I will post some pictures of mine soon.

WMno57

@bdugan You may come from a Forced Air background like me. I've owned and maintained forced air furnaces for 30 years. Only 2 years of boiler experience.

You and I have almost identical boilers. My 57 is set up to provide hot water to a bunch of 100 year old Kewanee Boiler Company cast iron radiators. Your 57 is set up to provide steam to your heat emitters. Our systems operate at different pressures. My gauge is called a tridicator and goes from 0 to +60 psi. Your gauge is for a steam system and goes from -30 to +30 psi.

Our boilers have different trim (controls, gauges, etc). We both have a Pressure Relief Valve (PRV). Mine is sprung to release at 30 psi.

bdugan

Here are a few photos. Please ask if you want a close up of anything.

EBEBRATT-Ed

Probably 1950s. If the boiler is not leaking and I was me I would replace the burner with a Carlin gas burner. Tune it up possible baffle the boiler and run it a few more years. You need a good technician with a combustion analyzer to do this. Do a heat loss on the house and adjust the firing rate at the lowest point possible keeping the stack temp and combustion in a safe range

WMno57

@EBEBRATT-Ed That is plan A for this summer. I may clean and inspect it before I make the investment.

bdugan

@WMno57: The "2" in 257 means two "banks" of fins or something like that, doesn't it? I am not sure but I think mine may have 3 or 4 of those. And mine has two header pipes coming out of the top.

The visible piping seems to be mostly in good shape from what I can tell. The dry return pipe has built up deposits right near the boiler. I suspected that check valve (near the bottom in the last photo) was stuck but I opened it up and I think its fine.

There is piping not shown here (behind the furnace) which is the wet returns and those pipes are in lousy shape. For several years I have planned in the winter to replace those in the summer, but I have not done that yet.

My house is a 3 story one built around 1860. I do not know when the furnace was installed. I was "installed" here in 1988.

EBEBRATT-Ed

@WMno57

next summer drain and flush the system. Install a couple of valves in the supply and return at least 5' away from the boiler (makes changing components and boilers a lot easier and saves draining and bleeding) Look for any potential leaks have a new burner installed and update the expansion tank and circulator pumps if need be

bdugan

This is a steam system, so no expansion tank or pumps. But otherwise all sounds like a good idea!

clammy

Your system from what I can see looks like a hot water system . You can look at it in one of two ways the first is , it’s paid for and quite old for its efficiency is it really worth throwing money at a boilers that’s what 50 to 60 years old minimum ? The other side is at some point you will move and either the home inspector or possibly the buyer or finance company may not be as keen as you on a old boiler . I personally wouldn’t throw any money at it but what I would do is start looking at options by first doing a heat lose to find the correct size boiler for your home next deal with a issues as for distribution in your home like under preforming areas . Most importantly would to have the correct contractor doing the work who is familiar w older hot water systems and knows how to deal w gravity and or large water content systems . The one thing for sure is your fuel use will be at mim 30 to 35 lower conservatively speaking . Don’t forgot possible liner for your chimney . I have removed a few of them ions ago and boy they where heavy even apart Peace and good luck happy holidays clammy

WMno57

clammy said:

Don’t forgot possible liner for your chimney

The chimney condition and cost of liner may make some decisions for me.

WMno57

I'm blessed to be at point in life where I could care less about making some future home inspector or buyer happy.

The other issue is if I tried to guess what would make them happy, I would guess wrong.

I'm gonna make me happy!

WMno57

@bdugan I like the enclosure on the front of your boiler that covers the burner.

Who made the Cadillac of boilers in 1950? These WMs have certainly held up well.

EBEBRATT-Ed

@WMno57

Liner and chimney would have to be done with an upgraded burner or with a boiler change so that's a wash. Liners are not big $$$ and the labor isn't a big deal. Unless the chimney is in bad shape it's not an issue

EBEBRATT-Ed

@WMno57
Most all the old boilers from that era were good. They lasted a long time because they were not pushed hard like the boilers made now. They had a lot of iron in them compared to there but rating

The new boilers are smaller and have less metal so they don't last as long

But the new boilers heat up faster and the old boiler had a large standby loss, so pick your poison

Steamhead

If those 57s are 3-pass boilers, it might be possible to baffle the flue passages so the hot flue gases have better contact with the cast-iron, which reduces the stack temperature. This was very common during World War 2 when fuel was rationed.

The other point is that those boilers might have asbestos insulation under their outer jackets. This would make replacement a lot more expensive.

The Midco gas burner in the one 57 isn't great, a Carlin EZ-Gas would be better if you can't get good combustion out of it and don't replace the entire boiler. The Beckett in the other one will run well when properly set up.

WMno57

@Steamhead I had read your post before about the water heater baffles.

https://forum.heatinghelp.com/discussion/170456/door-mount-disaster-or-ohhhhh-this-is-just-wrong

The doors on that National Heat Extractor boiler look similar to the doors on my WM 57.

On my 57 the Midco is mounted in the base, and the flame has probably been impinging the back wall for 50 years.

Techs by me don't do combustion analysis. There is almost zero steam or fuel oil around here. Maybe 1 out of 100 homes have hot water boilers. I doubt I could get a Pro around here to install a new burner my 57. They would all want to sell me a new boiler.

I posted this thread to learn more about the Weil Mclain boilers. I'm interested in the technology of the time, how the 57 evolved from the snowman boilers, and how today's boilers have evolved from the 57.

Fingers crossed, I won't have to do anything till this summer.

Steamhead

@WMno57 , where are you located?

WMno57

WMno57

WMno57

Touch Screen Display circa 1950

EBEBRATT-Ed

Yeah, the Midco is not a great burner. I would put a Carlin in. As far as flame impingement on the back wall that isn't a problem it's firing in a combustion chamber.

If I am not mistaken the flue gas comes up the sides of the boiler vertical and into the right and left flue passages then into the center flue passage and out the back. You can baffle it with a fire brick or two where the flue pipe connects to the boiler provided you have enough draft

Steamhead

I don't know, @EBEBRATT-Ed - that flame is looking pretty yellow where it climbs over the firebrick. I'd want to test it for sure.

It seems that firebox is rather shallow front-to-back, compared to the length of the boiler. This may be due to the flame pattern of the oil burner it was built for. The Midco E20 is known for a long flame pattern, and will impinge on a shallow firebox. Too much impingement will produce CO, even on firebrick. I've gotten much better results using Midco EC or Carlin EZ-Gas burners.

EBEBRATT-Ed

@Steamhead
agreed. I don't like the look of the flame either. The OP mentioned back wall impingement so that was what I was thinking of but that picture is bothering me. Almost looks like the burner is firing back inside the chamber front wall

Must have great draft though LOL In one picture the burner is firing with the fire door and flue door open!!!

I am sure someone with an analyzer and a new burner could fix that up to be much better

WMno57

In the first picture with the big yellow flame there is a bunch of crumbly white stuff on top of the firebrick. Is it scale and ash that has fallen off the back wall, or asbestos? I've left it alone because I don't know.

Does the fire brick make the bottom half of the fire box an open top combustion chamber? Is the fire brick there to protect the iron or reflect/direct the heat? The flame looks better with the doors closed, but there is still some yellow.

I think this boiler was oil fired for the first 20 years. Then switched to the Midco for the last 50. What is the most common failure point for old boilers? Do they rust through from the water passages? Do they erode from flame and combustion damage? Or do they crack from thermal cycling?

I know some would say, who cares, it's an old boiler and needs to be replaced. Maybe so, but I'm amazed it has lasted this long. I hope these pictures and discussion help others. I know I have learned a lot from reading threads on this site.

Thanks

WMno57

EBEBRATT-Ed said:

Must have great draft though LOL In one picture the burner is firing with the fire door and flue door open!!!

Steamhead, Ed, and the other Pros know about the Stack effect. I'm posting this for others who might be interested in how this works.

https://en.wikipedia.org/wiki/Stack_effect

EdTheHeaterMan

That boiler was designed to be hand fired. hence the big front door for shoveling coal. The bottom section where the burner is, had a door to remove the ash from the bottom. So the flame was designed to be up near the bottom door, just under the crown sheet of the boiler combustion area.

In the late 1930s and '40s, the more affluent converted them to fuel oil. During the war, all the metal manufacturers went into "war mode" and very few boilers were made in favor of Tanks, and Boilers for warships. After the war, any of the old coal boilers that were in stock were obsolete because everyone wanted the new-fangled oil heaters.

Boiler manufacturers scrambled to sell off the old design stock by making a base box that accommodated an oil burner in lew of the ash cleanout door. Not the most efficient design but who cares, we had a growing economy in the late 1940s.

As fewer and fewer consumers replaced their boilers with coal-fired systems, the engineers made smaller boxes to cover smaller cast iron boilers with smaller combustion chambers built into the design. No more after-thought combustion chambers. So the WM model 67 was born. then the 68 then the GO after that. Since the 1950s WM has had a similar design on the oil boiler and a dedicated gas boiler that has not changed much over the years until the condensing boilers started to become popular in the late 20th century.

Weil McLain's most popular oil boiler is still a design similar to the 67 from the 1950s

So as far as your gas burner in the water boiler, I have seen that model 57 boiler (in good condition like yours) burn very little fuel and operate at efficiencies as high as 79%. If the doors fit well and there is very little air leakage (as yours most likely is) then it is tough to make a case for replacing the boiler with something more efficient. Saving 40% of a very low fuel bill won't justify the expense of the replacement boiler. And you might not get those 40% savings anyway.

On the other hand, @bdugan's steamer will not qualify for a condensing boiler. His system is also fine with proper maintenance. I never liked the front cover as a service tech working on them. But they sure make them look good.