Water hammer - novice question

stevesorenson

Regarding Jamie Hall's question about other horizontal pipes near the water level… the only one I see is below the return trap where there is a check valve. This is just about exactly at the nominal boiler water level height.

mattmia2

that whole wet return and trap was well below the water line of the coal boiler. that check valve was likely a misguided attempt to fix the new boiler's water line being too low half a century or more ago.

if there is much of any pressure differential between the mains and the returns that will push the water out of the wet return and allow steam to follow those drips and the wet return between parts of the system that should be isolated by the wet return

mattmia2

the cracking pressure of that check valve could also be causing condensate to stack up somewhere it shouldn't be

or it could have been part of the original vapor specialties

stevesorenson

I truly appreciate everyone's prompt input on my newbie questions. I'm presuming the water hammer, besides being annoying, 1) contributes to premature pipe/joint wear and 2) makes the system less efficient. Or have I missed something important.

I'm thinking to get some contractors over to see what it takes to make it like it should be. The diagram below is pulled from the Dunkirk PSB manual, so I would say "make it like that". Make sense? It won't be cheap, I'm sure, and the boiler is already 32 years old. Neither of the techs who have been over have raised concerns about the boiler itself (they said it was in very good condition), though neither of them said anything about the piping arrangement being screwy, so not sure how much weight to give their opinions.

Someone mentioned checking the steam trap in vs out temps with an IR thermometer. Good idea, thanks, I just have to get one.

mattmia2

if there are wet returns that are right at the water line you should add a false water line to that I think but those that know vapor systems very well may have some comments about the implications of that.

if you have a wet return that is right at the water line, pressure in the boiler (and thus the mains)could be pushing water up the drips. that might be the mystery of your changing water line.

stevesorenson

Sorry, not following what a false water line is…

OK, now I am adding a few random observations, which may or may not mean a #$%#% thing…

1. Having failed to acquire an IR thermometer so far, I am checking radiator steam traps by feel. All the radiators seem to be giving off uniform heat across the entire radiator. Several traps are warm on both side of the trap (at or approaching the temp of the feed line). Some are cool to the touch on both sides of the trap. One or two seem to be cooler on one side of the trap vs the other. One or two overhead return lines in the basement are noticeably warm as well, while most are cool to the touch. The hot traps seem to be mostly, but not exclusively, on the first floor.

2. There are a couple of pressure gauges above the pigtail. They seem always to be more or less near zero, so I am not really sure what their purpose is. One of them is today showing me a slight vacuum of almost -4 inches of mercury (burner is off). When I have paid attention to it before it has been close to 0. The smaller one is always stubbornly pegged at 0.

What are the references (books/websites) I should have in order to understand these systems as much as possible and avoid silly questions? I am coming from the perspective of a reasonably intelligent human having no prior experience with steam heat.

mattmia2

the lost art of steam heating

https://www.heatinghelp.com/store/detail/the-lost-art-of-steam-heating-revisited/

a false water line is basically a high loop in the return piping before it connects to the hartford loop that makes the water level in the system returns higher than the water level in the boiler.