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The cause(s) of this near catastrophic had several contributing factors.
1- The boilers would constantly flood. The question was how? After we had corrected a number of issues, we had steam up and found that when the boilers cycled on pressure that there was a vacuum low enough to induce a siphon from the feed tank even though the piping was 10 feet in the air. This vacuum filled the boiler. A couple of checks for vacuum breakers took care of that.

2- The return lines were almost 100 percent plugged. Lots of cutting and piping were done to clear the returns in the boiler room.

3- There were a mass amount of leaks in the system, both steam and condensate. Most have been addressed.

4- The vac pumps that controlled flow to the feed tank were working at about 10 percent when there was water that returned. The piping has been repaired but the controls will still require rewiring.

5- Currently operation on the reset control and maintain the building at 68=70’f

6- The system MUW has been very low and the chem is maintaining PH and TDS without much effort.

7- The former MUW bills had to be massive.

8- New pads were poured as the old pads were broken up pretty well

9- From start to finish, about 6 weeks time. It was a miracle that there were two LGB13 boilers in town, that the weather held off and that we could make parts work until OEM parts show up.

Take a gander at these images.
If I am correct, they were loaded with chemicals, over filled and cooked and then dry fired.
The gaskets were melted between the sections in most cases and the ignition controls were melted off and hanging

Anyone seen this before?

As a comparison I have a older home single pipe and for a 2 degree temp rise from a cold start ,after the system has steam to the main vents it usually takes about 45 minutes to 1 hour for the stat to be satisfied . I think there a lot of widget room in there especially w a counter flow system being there’s only so fast you can vent everything through the radiator . If all else is kosher I would look to possible increase the radiator vents from 4,5,&6 to 6 ,c and d . I find in older system the owner best bet is limit set backs to only 2 or 3 degrees ,there seems to always be issue w either slow recovery ,start up cycling on low water due to heating mains until piping is hot enough to prevent excessive formation of condensate . On slow reacting system if I have personally pulled the boilers return plugs and washed out the boiler of it mud and debris and upon re firing found the system slow response had a lot to due w mud build up in the boiler directly effecting the boiler abililty to produce dry steam and to transfer all the burner heat to produce that steam . I ve done this on quite a few boilers who,s Performance was poor but piping and everything looked better then most just going on a hunch I drained the boiler from a 1 inch ball valve directly on my boiler spare return tapping ( 21/2 x1 1/4 reducing ell) seeing the real condition of the water ,drained wanded from bottom and top filled and a fast skim ,afterwards the mains went from 45 minutes to about 5 minutes all due to poor water quality . As clean as a sight glass is it truely isn’t the indicator of the internal cleanliness of the boiler . Often discounted is the internal cleanness of the boiler .
I find out of all the types of steam system out there that counter flows are often the toughest being you truely need dry steam for any type of decent performance . I ve found that an over head feed off a drop header w the header take off being tied into an upward facing tee piped into the run and the Start of the fitting continues and drops into your wet return . I ve usually always used a vapor stat instead of a pressuertroll . If the boilers is short cycling I would probably recheck the edr and if oversized possible add a 2 stage gas valve to get a longer cycle and less on and off cycling . I never discount a dirty boiler ,you never know until you pull the boiler plugs it seems to be the thing nobody does but if installed without provision to due so ya might as well wait till it kicks the bucket .
Peace and good luck clammy