two pipe hammer

kcopp

I looked at a system yesterday in an area that is out of my normal service area. (about 1.25 hrs from me) The homeowner was "desperate" as he has had 3 or4 other contractors out who had no clue.
I am no "expert" but as Dan says...." in the land of the blind, the 1 eyed man is king"

He as lived in the very nice 1928 Tudor home w/ a 2 pipe steam system in it, for 1 year.
4200 sq. feet.
The boiler was replaced in 2011. They installed a W-Mc 480 series boiler w a huge gas burner.
It has to be 50% too big.... rated at 1238 edr.....and surprise, surprise not piped right.

He has 2 immediate issues. I section on cast iron baseboard that don't get warm and another area at the end of the run that get plenty hot but at the end of the cycle hammers like a banshee.

I am guessing that the cold baseboard traps are not opening and the hammering is from a trap that will not close...

Let me try to figure how to post pix off my phone....

kcopp

lets try this.....

kcopp

Few more of the boiler...<img src="https://us.v-cdn.net/5021738/uploads/FileUpload/92/2eed5e17902dd6e54bcfb747ef0d34.jpeg" />

kcopp

What brand are these ? I see the "cross over" may be a Tunstall.

Jamie Hall

At least one Hoffman cross over trap there... and a differential loop...

A Hoffman equipped system Therefore -- anything over 12 ounces is going to be trouble. What is the vent on top of the differential loop? It should be a big Hoffman -- 75 or 76. You can, if more main venting is needed, replace it with an antler and as many Hoffmans or Gortons as you please, but keep at least one big Hoffman there, in the position closest to the connection to the loop.

Do not put any vents, main or otherwise, anywhere else in the system. If you find some, pull them and plug the holes. You can move them to your antler at the loop if you want to.

But yes, I'd think that the cold baseboard strongly suggests a failed closed trap, and the hot are more likely to be a failed open

kcopp

Any direction on what part I need to order to repair? ty

Fred

That wet return where those two drips are connected looks pretty high. Is it above the water line?

Jamie Hall

Fred said:

That wet return where those two drips are connected looks pretty high. Is it above the water line?

Good question. I hope not. But it should be checked -- and any other bits of wet return.

As for what part to order -- first thing to do is to find the errant traps and see what they are.

If you can convince the client... you're going to need a vapourstat, if they don't have one, or you'll never get it working right. If the boiler pressure goes over 12 ounces (sometimes a tad less) the Differential Loop lets steam into the dry returns (which is what it is meant to do; it ain't broke, don't fix it!) which you don't want.

kcopp

The wet return is below the water line.
The copper section was leaking just before they bought the house and then replaced it w/ 1 1/4 copper.
The other contractor flushed out the entire return.
There is a vaporstat on the system along w a presuretrol.
The hammer is coming from the area w the tag on it...well above the water line.
The pictures show the traps that need to be replaced.
TY

Jamie Hall

All good. Both of those traps can be rebuilt -- but someone else will have to tell you where to get the parts.

The vapourstat is excellent! It should be adjusted so that the differential loop never trips -- you can hear it when it does, and steam will get into and heat up the dry return right above it. If that happens before the 'stat shuts off the burner, try lowering the cutout pressure.

Is the hammer in the dry return there? Or the main?

kcopp

Hammer in the dry return. I can prob get the part....just need to know what to ask for.
TY

Steamhead

Depends on what model trap. The Hoffman looks like a #8, and I'm pretty sure that's a standard Tunstall. Tunstall carries parts for both traps. Just make sure you know the correct model for each.

kcopp

Thanks a ton! House is a real beauty.

Steamhead

Looking forward to more pics!

kcopp

Steamhead said:

Depends on what model trap. The Hoffman looks like a #8, and I'm pretty sure that's a standard Tunstall. Tunstall carries parts for both traps. Just make sure you know the correct model for each.

So you are right.... There are several replacement cages for each #8 and a few version of #8's

My supplier doesn't have anything for the Tunstall.
That actually looks new to the system, its shiny chrome...
Is it possible that that was replaced and it was the wrong trap?

It may be simpler to replace the whole trap.... Thoughts?

kcopp

Well I replaced the trap)s) that wouldn't open and the CI Baseboard now works! Great. I replaced the crossover trap and still have that rattle/ hammer on the return. I pulled off the insulation and lo and behild the part of the dry return was back pitched. Spent some time fixing that and still hammers on there. What do I do now?

kcopp

Here are some pix

kcopp

Here you go...

kcopp

I will try to post video

Fred

Did you check the full length of the returns and the mains? Also, those Pressuretrols on that manifold look really low. Is the base of those Pressuretrols below the water line? If so, they are not going to function to control pressure. You mention that the hammer is at the end of a cycle. Since the boiler is so over-sized, is it possible the hammer is a result of excessive pressure affecting the traps and/or preventing water from returning to the boiler?

kcopp

The gauge never moves off of zero.
Now that you mention it there is a pretty small line between the pressuretrols and the water line....
There is an identical loop on the other side that does not give a problem at all.

Fred

That old 0-30 PSI gauge isn't likely to tell you anything. You need a 0-3 PSI gauge on there to actually see what's going on. Besides, the gauge may be water logged as well. What is the manifold on the other side used for?

kcopp

when you say manifold.... you mean where the differential loop is?

Steamhead

Not sure what to make of the near-boiler piping. The 4-80 only needs a single 4-inch riser and a 4-inch header.

The control setup will never work well. We like to mount the controls on a manifold coming from one of the 1" tappings at the top front of the boiler. This way, dirt can't wash into it.

Fred

I'm calling that pipe that all the Pressuretrols are mounted to a manifold. What's on the other side that you refered to?

Steamhead

Something like this. This boiler has lo-hi-lo firing so there are three pressure controls, but you'll get the idea:

http://forum.heatinghelp.com/discussion/153445/boiler-replacement-on-larger-webster-type-r-system-finally-ready-to-post

kcopp

What they did was pipe out of 1 side (front) of the house for 1 riser and out to the rads and the other riser to the (back) side.
they all run back to 1- 1.5" return. See the 1st set of pix.
The piping is not great.
Apparently in the largest city in NH they have a hard time finding someone to follow instruction manuals.

Steamhead

Manuals? We don't need no stinkin' manuals......

kcopp

Steamhead said:

Manuals? We don't need no stinkin' manuals......

My biggest pet peeve showing up to a job.....
Question... "where is the manual?"
HO... "I have it upstairs in a file cabinet..."
My answer... Why? It does a lot of good up there when I need it here!"

kcopp

https://www.youtube.com/watch?v=g39i8fYk2EQ

Steamhead

I bet the point where those two drips tee together is very close to the boiler's waterline or maybe a bit higher. Steam is getting down in there and causing the banging when it hits some water. That's probably why the piece of copper was installed- the banging caused a leak.

Check the levels, and lower the connection point below the waterline if needed.

kcopp

You are right about the copper. Just before the present owners bought it the pipe was leaking. ...cant figure out why they went to copper AND reduced it to 1.25" from 1.5".
Do I need to lower the pitch of the entire line? if I have to do I trap it?

Steamhead

Yup- the entire wet return must be wet, that is, below the boiler's waterline. The lower the better. You don't need a trap, as the water standing in the lowered return line will keep the steam from entering.

kcopp

Steamhead said:

Yup- the entire wet return must be wet, that is, below the boiler's waterline. The lower the better. You don't need a trap, as the water standing in the lowered return line will keep the steam from entering.

Sorry... when I said trap I meant can I drop the line down say 6" and create a "trap" so water makes its way in there.
Otherwise to re-pitch the line its 50' of re-pipe.

kcopp

Update...
I relayed this info to the customer.
He went to the boiler and added an inch of water to the water line....
He emailed back that the silence was deafening!
ty,kcopp

JUGHNE

Was this similar problem in another recent post? I believe just dropping the two drips to the floor and then back up to the existing horizontal return might have helped.

Of course that new trap/loop would be sludge trap needing cleanouts. Where are any air vents located?

Note: that previous post has a discussion about the cost of concrete blocks to raise the boiler to get closer to the original water line.

Steamhead

That confirms it.

You might be able to simply adjust the pipe hangers to lower that end of it, then extend the drips. You technically don't need any pitch to make that return work, but the entire return must be below the waterline so air pockets can't form. If you end up pitching the return away from the boiler, put a boiler drain at the drip end for draining and flushing.