steam boiler

[Chad Fabry]

There's fresh rust coming from the seam between the first two sections on this boiler. I watched it for 20 minutes on and off through a heating cycle and saw no evidence that it actually leaks still.

It's 30 years old and is absolutely huge for the house it's heating...1700 square feet with 224,00 btu input. It can't be efficient

I'm struggling with recommending repair or recommending replacement. I hate to defer to the hvac guy. So I'll defer here instead.

First pic is the rating label

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Second pic is a chart...maybe someone can explain it to me

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This last pic is the new rust

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[Bain]

Hi Chad,

Unlike some, I don't see a surfeit of boilers, but have attended enough seminars to know my way around most systems I come across. Having said that, I hate to defer out, but normally do when it comes to boilers just 'cause the boiler-certified guy knows the kinds of problems different models are susceptible to since he sees them more often than we do. I have a dear friend who's an inspector and a master-certified HVAC contractor. When I call him with a question, the first thing he asks is, "What's the brand and model number?" because he knows which models are prone to particular problems. The same holds true for boilers. At thirty years old, I'd tell the buyer that you have some concerns, and recommend that a boiler-certified HVAC contractor assess the system. I'm assuming that like me, you feel as if deferring out is rather wimpy and CYA-ish, but it's perfectly reasonable when a system is 30 years old. And if it's any comfort, my master-HVAC friend does the exact same thing.

[Neal Lewis]

Chad,

Comparing the two charts, I would say that the net capacity is 129K for the 4 section boiler; may not be oversized. Did you happen to overfill the boiler above the area of the rust and watch for leaking?

[Chad Fabry]

Thanks for the help.

Neal, I now see what the size chart is about and that the four sections are probably appropriately sized for the residence.

I did not fill the boiler to check the leak. The water level was about 5 inches or so below the origin of the stain. Since the water is never above the stain it must be leaking during normal operation. The unit was running at .5 lb of pressure.

[kurt]

We call those "section leaks"; a tiny amount of water works it's way out around the gasket, and then after a while, it "repairs itself", probably by gunk sealing up the tiny hole.

Most of the time they're not a significant problem; at least, I've never seen a tiny section leak turn into anything significant; it takes a fairly long time. I've been watching a section leak @ a friends house now for about 10 years.

Given it's an HB Smith, I'd say they have a few more years on it; low pressure steam boilers around here easily go >30 years.

[Jim Morrison]

Hey Chad,

HB Smiths are only guaranteed for 20 years, but I often see them at age 50 and up. If it were mine, or a friend of mine's, and I had the twin luxuries of time and no liability, I'd probably just watch it until it got worse, which as Brother Mitenbuler points out, could take ten years or more.

However, when I come across a leak like that on an inspection, where time is very short and liability is very high, I'd fire the boiler for a little longer than usual to see if I could get it to leak. Chances are very good that I'd be advising my client to get it checked out by a heating contractor right away.

Even if it only needs a new gasket, that can run $1500.

When it's 4th and long, I punt.

[kurt]

Yes, it's one of those things that I point out, tell the folks what it means, do all the usual notifications, and the guy comes out & tells everyone that it's not a big deal right now, but it could be, or some such shuffling like we do 'cuz no one can tell for sure without taking it all apart anyway.

Those things get a whole lot worse looking than that before anything significant goes on.

Someone correct me if I'm wrong, but almost all boilers go @ the head, not the bottom; they run dry, or too hot, & the head cracks or the gaskets open up, or they last about 40+ years & then the sections start being a real concern.

I see a lot of low pressure steam boilers that are >40 years.

[Chad Fabry]

The boiler at my shop leaked between the sections for about 8 years. The resulting rust build up expanded and broke the ears off where the retention rods held the boiler sections together. I'm glad I wasn't standing there when it happened.

[kurt]

Yeah, exactly. The suckers get nasty bad rusted & delaminated, & one can pretty much read it depending on the amount. If it's just that "foamy" rust and the delam in minimal, I've found them, in general, to hang around for a lot of years.

Or not.