3 Weil Mclain boiler sections rotted?
Ok, so I'm told by the people who installed the boiler in my building (I think it's a wm 80 commercial oil boiler?) three sections rotted and rusted due to excessive replacement water? Weil Mclain (without ever seeing the site, condition-or anything) agreed this was the case.
So-being a non-plumber, I have asked 7 very highly regarded plumbers, and a city inspector if they have ever heard of this....not one has ever heard this in their careers (ranging from 10-35 years). Two plumbers told me there is something on the boiler to regulate the water going into the boiler.
Has anyone ever heard of this happening? Anyone. Thank you for reading!! :eek:
Cast iron sectionial boiler failures, repeated multi cracked sections
Even thought this is an old thread, I came across this looking for cast iron boiler section failures in an investigation that I am currently involved in. Cast iron boilers don't rot. What most often happens is one of two things that cause cast iron sections to fail. Before I continue, excessive make up water due to what ever reason will cause tube failure in steel boilers and some may will call this "rot". Cast iron sections will fail due to the introduction of cold make up water into a dry (water absent from the boiler sections itself) and the boiler has been "dry fired". This is why they have low water cut out controls on water and steam boilers. This type of failure is common on cast iron steam boilers when the water level control is not working and make up water is added by "hand" to a red hot boiler. Just like adding water to a car engine when it has overheated and you are not willing to wait for the hour or two to let the engine block to cool down. You will crack the cast iron block. Steel boilers will not do this, they have a much greater coeficient of expansion.
The other issue that brought me here in the first place is one much more difficult to diagnose. Boiler section failure in exactly the boiler type and manufacture of the one above. These sections are used by a few manufactures as not many foundries exist in the US any more and a number of different product lines use the same castings. These particular cast iron sections fail usually in the middle sections. The boiler is standing by "hot and satisfied" with no call for heat and is satisfied lets say at 180 deg f. No water is circulating. A zone calls for heat that has been sitting idle all afternoon on a sunny, mild winters day. The sun is setting and the zone now calls for heat. The pump starts, no 3 way modulating control valves are on this zone. Just a pump with a large amount of piping and radiation, or maybe a very large coil in duct work (again with out a 3 way valve), This huge slug or flow of relative cold water lets say 75 deg f. water hits this 180 deg f. water that is not mixing well creates a condition called thermal shock! Cast iron can not expand/contract quick enough and the cast iron gives in the only way it can satisfy this need to move and something must give. The cast iron will crack.
The "job" I have in mind had steel boilers which never had a problem and a contractor decided that cast iron was the correct replacement choice. I have seen jobs that cast iron replaced cast iron and for the first time sections started to fail due to thermal shock. Why not the other or original boiler? Water flow design and quality and thickness of the castings themselves. Solutions do exist, they can be found in a number of changes and modification to the way the piping is to be made up for these boilers. To my knowledge they are in the at least the 3rd generation of modifications to rectify this issue.
Now whats important to me. I would like to hear from anybody who has had repeated/ongoing commercial boiler section failures and can give me the correct and detailed data to include but not limited to the boiler model and manufacturer, number of sections, burner type and fuel, steam or water, age and application. I in turn will help you correct failures with suggestions to correct the issue and suggestions to aid you in dealing with the legal aspect of this defect. Thanks for your time.