Back pitched wet return

SeanBeans

May be a stupid question.. but will a back pitched wet return shared by 2 mains cause water hammer?

What other symptoms would this present?

Thanks guys

Fred

If it is truly a "wet Return" meaning it is below the boiler water line, pitch of a horizontal pipe really isn't important. It is filled with water all the way back to the vertical drips and those drips are filled with water up to the boiler water line.

SeanBeans

Okay.. thought i was missing something. Thanks @Fred

JUGHNE

One concern would be is the height of the water seal in the returns relative to the HL and boiler water line. IMO

ChrisJ

JUGHNE said:

One concern would be is the height of the water seal in the returns relative to the HL and boiler water line. IMO

Why would the pitch of a wet return effect the height of the water at any point @JUGHNE ?

JUGHNE

Not the pitch causing my question, but how did it get there?
Maybe some cobbling by previous boiler installer.
I am imagining some one raised it up perhaps loosing some height of water column on the return.

There was one posting where not raising the boiler on 4" blocks dropped the water level in the return causing hammer.

We don't have the whole picture for this system.

Fred

In the case you refer to @JUGHNE , not raising the boiler by those 4 inches made the wet returns dry. In this case (and as I tried to clearly state to @SeanBeans ) if the wet return is truly a wet return, below the boiler water line, he should be fine.

Lance

Wrong or poor choice of pitch can cause sediment collection. Possible future problem or maintenance chore.

Paul48

Really?

Fred

Lance said:

Wrong or poor choice of pitch can cause sediment collection. Possible future problem or maintenance chore.

Those wet returns should be flushed out annually as part of maintenance. I agree, the pitch may change where the sediment collects but it is going to collect somewhere between the vertical drip and the Hartford loop anyway and it all should be cleaned periodically.

JUGHNE

He is working on a hammering system that was probably hacked before he got there.
We don't know without his input if perhaps these were supposed to be dry returns that someone turned into uphill sloped wet returns.
We have seen almost everything wrong that is possible done on this site.

Fred

@SeanBeans , you say that wet return is shared by two mains. Do those mains also share the vertical drop into that wet return? If so, are they tied into that drip above the water line? That could cause hammer.

SeanBeans

This is actually from the job from my discussion labeled 'tomorrow..'.

At first glance it looked like it was back pitched but it was exactly level. The customer says that 'some banging came back'

He said its either first thing in the morning or in the middle of the night, unfortunately all of the near boiler piping isn't insulated and probably won't ever be insulated unless he decides to tackle that himself. House was built in 1929 and it looked like people added 2 rads over the years in copper piping.

Fred

Have the homeowner try to narrow down the location where the hammer is coming from. If those wet returns are well below the water line, it won't be from there but now that you mention a couple rads were added, with copper, I'd start looking at how they were plumbed and if those feeds/returns might be level or pitched the wrong way. How are they tied into the main?

SeanBeans

When we tore out the old boiler there was an indentation in the ground from what looked like the original boiler, roundish indent.

Jamie Hall

SeanBeans said:

When we tore out the old boiler there was an indentation in the ground from what looked like the original boiler, roundish indent.

Look around and keep looking for some dark lurking corner where what should be a wet return -- or a couple of drips into a wet return -- isn't any more... the water level may have been lowered.

Also those added radiators -- check and double check all their piping. It's OK, if not great, that they are in copper, but if they can't drain properly they'll bang. One possibility which is a bear is if one of the steam feeds to those is just level, or even slightly sloped, and the pipe is small (which I'll bet it is), it may bang badly for a few minutes on a cold start (copper condenses a lot of steam!) but otherwise sit there and grin at you. Been there...

JUGHNE

Did the hammering start after you changed the boiler?
Do you know the level from the floor of the boiler you took out?
The original round boiler most likely had a pretty high water line.