Short-lived boilers

John_194

So the operator (homeowner) is supposed to manually feed the boiler to maintain water at a higher level? The O&M manual doesn't mention this.

And if it is cracking, not pitting, what other things does that point to?

John_194

Short-lived boilers

My second boiler has just sprung a leak after only 10 years. The first one was only a few years old when I bought the house and it lasted only 9 years (for me). The service man said the water line was too low causing the boiler to overheat and cracking the boiler. The failure points in each case are at or slightly above the water line. Can a boiler overheat? What does it take to allow a boiler to last a reasonable amount of time - 20 years or more? Am considering changing to a different heating system.

Brad White

Steam I take it?

A good steam boiler should last 30-35 years while the system to which they are connected can last over 100.

Where such failures occur I can see as a function of system failure and not an overt one. A chronic leak in a buried return can cause unchecked make-up water (fresh O2) into an otherwise minimally oxygenated system. An automatic water feeder can contribute and mask such a condition. It can also, because it is a dumb device, allow cold water into a hot boiler should the LWCO not act promptly. A host of suspects, it may not be the boiler. In fact, I think the boiler is the victim. Col. Burnham, In the Boiler Room, with a Pipe Wrench. But I do not have a Clue (tm)

EDIT- Especially in light of what Noel said: The water line is a violent place, where steam, water and air (oxygen) are in competition. I have seen stainless steel open tank humidifiers with pitting perforations ("Tear Here!") all along the waterline. And this was a tank not even near boiling- just had a gravity HW immersion coil but with constant make-up water. It was a humidifier after all. Go to boiling and you really have something.

John_194

Short-lived boilers

Yes, it is steam. One-pipe steam, although the upstairs used to be two-pipe until someone converted them to one-pipe, but that's another story. The system is 1928 vintage. The return is a dry return so there is no leakage that I am aware of. The way the low water cutoff is piped puts the water in the gage glass at about one-third up from the bottom. The service man says it should be half-way up. The previous boiler did the same thing. My original post was to see if boilers are made to last. Or if they are not being made a good as they used to be.

Unknown

Pitting (not cracking) at the waterline

is an indication of lots of make-up water and the oxygen it carries with it. Cracking points to other things. When it comes out, split it open and see what the waterline looks like.

The water feeder only maintains a barely safe water level, the operator is supposed to keep enough water in it that the feeder only operates in an emergency.

Noel

John_194

good steam boiler

You may be right, but what is a "good steam boiler" that should last 30 years? With the violence described at the water line it sounds like there is no hope of survival for the long term.

And what about summer layup. The boiler sits there all summer with water in it. Is that a recipe for corrosion at the water line?

Brad White

I can say at some risk that

Burnham. Crown, Peerless and others make good cast iron boilers. Any boiler can have a failure. I have seen H.B.Smith boilers installed in the 1890's working well 100 years later. It all depends on if the piping is tight. Leaks happen and can be repaired. If ignored, it is feedwater time.

My point about the waterline issue is that with lots of water added (that is the key part), corrosion is accelerated. The idea is that you NOT have that make-up water.

In summer, the dead water sits there. Not a lot happening. Many are laid up wet, some dry. There is a range of opinions on that score. Mine were always laid up wet.