Hammering on newly installed boiler

arbalest

I've searched the archives and I have read the checklist but I still have a few questions. I posted this question at DIYchatroom and it was recommended that I post here.

Anyway, the installers finished this yesterday and did some skimming which was to stop the hammering that I was experiencing. But, I woke up in the wee hours this morning to the sound of more hammering. I skimmed some more but wound up turning off the boiler. I turned it on a bit later and had the same issue. The full cycle (repeatable pattern) is this - the boiler runs without hammering, the LWC stops the burners for a moment and lets in more water. Then the burners come back on and shortly after that the hammering really starts.

I want to have a handle on what is happening before I get the installers back here. With this post I am trying to determine first and foremost if this is:

1) a normal process that is handled by skimming
2) an incorrect installation
3) an incorrect boiler size
4) something else

The installers used as much of the existing piping as they could but the boiler and all of the controls are new. The attached picture shows:

1) The silver painted pipes are the originals.
2) A 12" offset added to the riser was needed to align with the existing pipe.
3) The return pipes are original but the h-loop equalizer is the black one on the right. I've read that the returns should tie to the h-loop with a close nipple. Due to the height difference they created the double elbow thing which must total about 12" inches. Below that is a stub for maintenance and a tie in to the feeder valve.

Any input is highly appreciated.

ChrisJ

Wow that's a lot of pipe dope.

We need pictures showing the read of the piping but it already doesn't look good.

arbalest

Adding two more pictures to show the installation details at the top.

ChrisJ

Perfect.

Can you supply pictures and or dimensions of all of your radiators?

ChrisJ

Do you have an idea of what size boiler that is? Looks like an EG-65 maybe?

Just going by the pictures you've provided so far, the boiler is piped wrong and likely way too big, but need to know how much radiation you have first.

KC_Jones

Things that I noticed right away.
1. Hartford loop is wrong. Return pipes should drop almost to the floor then rise up into the Equalizer.
2. The attempt at a Hartford loop should have had a short nipple at the equalizer not the mess it has now.
3. The equalizer connection at the top in what they are using as a header is wrong. They have a reducing tee and that will cause a damn for water to backup. The steam will pick up this water and probably hammer like mad. That reduction for the equalizer should be in the vertical NOT the horizontal. Even though this is in the old piping it still isn't correct.
4. I see 2 return pipes, but only one steam main. Does the main split in the boiler room or somewhere else we can't see? When possible the mains should be connected into the header individually.
5. How did they size the new boiler? Did they just look at what was there or did they measure all the radiators in the house and size according to that? The second way is proper the first is not.
6. Where are you located? We may know a good steam person in your area, not all contractors know steam and it's painfully OBVIOUS yours does not and should stop replacing boilers.

arbalest

Answering the above -- I am in Chicago and got estimates from 4 of the top Yelp-rated installers who do boilers. At this point I would like to get it done by the person I have already paid but might need to go elsewhere.

They all measured radiators and 3 of them proposed 350K BTU and one proposed this one which is 300K BTU (EG-75). I also measured the radiators myself, used online calculators to determine sq ft of steam needed and the and looked at the specs of the 300K boiler and found that it was slightly bigger than I needed but within range. I didn't know what factor to allow for piping etc and I don't have my measurement info handy at the moment and I might have tossed them. The previous boiler was 375K BTU. Also, this is in a 100 year old brick 3 unit building.

The installer (says he) computed things himself and sent the measurements to the supplier for good measure.

As the header/supply pipes leave the boiler room they do branch out all over the place (unfinished basement but several rooms) and they go in and out of the basement ceiling so I don't know the routing details after they leave basement.

One of the reasons I went with this installer is that some of the others wanted to have someone else remove the pipe insulation so that they could replace more of the pipe. And that would have been a really pricey undertaking considering what they are made off (cough, cough). You can see that I have wrapped them to make them safer.

ChrisJ

But now you have a system that works very poorly because it's piped completely wrong.

KC_Jones

You don't want to look for people that "do boilers" you want to look for a steam boiler expert. Steam is a unique animal and alot of installers don't get that and do this garbage work. As for some of your comments about sizing, it's simple. Measure the radiators, get the EDR measurement in sq ft then compare that directly to the sq ft rating on the boiler, nothing else required. It actually kind of weirds me out that your installer felt the need to have the supplier double check. The only way that makes sense in my mind is if the supplier came to your building to also measure. Being in Chicago this is the man you want to call. I don't know if he is taking new customers, but he is one of the best in the country.
https://heatinghelp.com/find-a-contractor/detail/the-steam-whisperer-boiler-professionals-inc
As for what you have going on, they need to come out and basically start over. Until that piping is correct there is almost no way you will get it to run properly. Also the incorrect Hartford loop is actually a very bad situation. The Hartford loop is essentially a safety device and it should be corrected.

BobC

I agree that boiler is piped completely wrong, if you look at the piping diagram in the install manual you will see the way it should have been done. If you haven't made the final payment on the boiler. don't until it is piped right and working to your satisfaction.

On page 17 you will find the piping diagram, this is the MINIMUM acceptable piping. I would want both tappings used and I would want them to feed into a header that was at least 4" so you get nice dry steam; I would also ask they use a drop header - a bit more for the pipe but easier to setup. This is better than the minimum piping so I would expect to pay for the difference between the minimum piping and what I want.



Bob

SWEI

Among all the other issues, that boiler comes with two 3" supply tappings, both of which must be utilized.

Abracadabra

@arbalest I'd be interested in finding out who installed your boiler. PM me. As has been mentioned, all your near boiler piping is wrong.

arbalest

SWEI said:

Among all the other issues, that boiler comes with two 3" supply tappings, both of which must be utilized.

Are you sure that both MUST be used? The diagram in the manual for EG/PEG (which has been clipped off in the image posted by BobC) shows a single pipe.

Fred

On a boiler that size, both risers should definitely be used. If you do decide to get someone to do the job right, do contact @Abracadabra . He is in the Chicago area and he will get it straightened out for you!

Abracadabra

Absolute minimum is a single 3" riser. Around here, most of us like to go the extra mile and do better. using both risers is better and will create a slower velocity which in turn will help create drier steam.

BobC

One 3" riser would be the minimum allowed, it would perform better with two risers and a larger header. It would cost more so the owner has to decide if he wants to spring for it.

Bob

arbalest

Abracadabra said:

@arbalest I'd be interested in finding out who installed your boiler. PM me. As has been mentioned, all your near boiler piping is wrong.

While I want this done right, at this point I am concerned about jumping the gun and being accusatory and/or going on the attack by spreading his name. Of course, if he doesn't make it right I will do that and more.

Several comments above indicate that the piping is all wrong. But if the top connection to the loop is changed to a reducing elbow and the returns are joined to the loop with a close nipple to a vertical isn't that about it?

The joining to the loop is more than 2" below the fill level, as in the diagram (maybe 4"). Is that a must-fix? The bottom of the returns are below that but must they be below the return port on the boiler?

Update to post: OK, and a 2nd riser, etc.

Fred

I'm not sure I even see a Header. It looks to me like the riser goes up to the main and the equalizer is tied off of the open end of the main??? Not right

arbalest

Fred said:

I'm not sure I even see a Header. It looks to me like the riser goes up to the main and the equalizer is tied off of the open end of the main??? Not right

That seems to be the case. This is all new to me and I am not defending the guy but the previous boiler was in place for about 50 years. I know that doesn't make it right but in the 17 years we've lived here we haven't had a problem. We just replaced the boiler to be on the safe side. What am I missing?

Fred

Those old boilers had a lot more water and a larger steam chest in them, making them a lot more forgiving than the newer, smaller boilers. The purpose of a true Header is to help the water droplets fall out of the steam before it enters the Mains so that you have nice dry steam. Any water that drops out is then returned to the boiler via the equalizer. In your case, the water is probably being pushed right out into the main by the force of the steam, never having a chance to go in the reverse direction to that equalizer. That's why the proper configuration for the header and mains is Risers out of the boiler first, at the opposite end of the header from the equalizer, then your main(s) and then your equalizer after the mains. That way the flow of water is in the same direction as the flow of the steam getting to the mains.

arbalest

Thanks @Fred. That makes things much more clear to me and knowing the "whys" is always better.

In addition to not having a header, I have the riser on the same end of the boiler as the equalizer -- where the tee branches one direction for the steam and the other direction to the equalizer. Now I am sure to get this done even if the hammering were to stop after more skimming.

Fred

Your welcome. Keep us posted on how this turns out. Also, make sure when they put the header in that that header has a slight pitch towards the equalizer to help the water flow that direction. Doesn't have to be much pitch but a little bit helps a lot!

jonny88

Recommended piping is usually bare minimum requirements.As @SWEI said 2 3IN risers.Sorry for your bad luck.Sad to see.

arbalest

Firstly, thanks to all who have given me feedback so far.

I want to add a somewhat tangent comment here. After 30 years of of both hiring all sorts of contractors and doing a great deal of work myself I thought I was in tune with various contractors who give me what I need versus those that are pushing the scope unnecessarily to drive up the cost.

Now I've never gotten a new heating plant of any type but when some of the estimators said we'll have to replace all of this pipe, they never said why. So it sounded like the typical scope-creep BS. If any one of them had explained what was wrong with the current piping scheme and the whys and wherefores of a new scheme they probably would have gotten my business. As it is, the guy who said, I can just connect up to the pipes you have here sounded like the knowledgeable and genuine one of the bunch.

Live and learn.

Dave0176

It looks like you have one 2" riser coming from the boiler. If that is the case, your steam is leaving the boiler at a velocity of 89 ft per second. We like to shoot for 15 ft per second. The Weil McLain EG75 minimum piping spec lists a single 3" riser which will get you down to 37-38 ft per second. We would use two 3" risers on this boiler which would lower velocity to 18-19 ft per second. You also need a properly piped minimum 3" header to help remove water from the steam. We shoot for a 4" header on a boiler this size.

What this all means is the steam is leaving sooo fast it's pulling gobs of water outta the boiler with it, which is more then likely adding to your miserable water hammer.

Please look over the Weil McLain manual thoroughly and then demand that your plumber please re pipe your boiler to the manufacturers minimum specifications.

vaporvac

Here's a pertinent article from the archives on this problem as well as a great little video showing the whys & hows of correct near boiler piping.
https://heatinghelp.com/systems-help-center/category/steam#water-hammer-in-steam-systems

https://heatinghelp.com/systems-help-center/near-boiler-piping-video/

arbalest

Dave0176 said:

It looks like you have one 2" riser coming from the boiler...

It is actually a 3" riser but I will pursue getting it redone with 2 of them. Thanks for the detailed information on the velocities and the effect it has on pushing out water. I can see this in action as this morning (when the thermostat first moved over the the morning schedule) the boiler started out with 1 minute cycles -- pausing to take in more water each time! After plenty of water was up there (5 cycles or so) the hammering started.

arbalest

vaporvac said:

... as well as a great little video showing the whys & hows of correct near boiler piping.

Thanks. That is sure one clear and concise explanation.

ChrisJ

arbalest said:

vaporvac said:

... as well as a great little video showing the whys & hows of correct near boiler piping.

Thanks. That is sure one clear and concise explanation.

Dan's the best when it comes to things like this.
It's a shame even with his books, and videos like this and even pretty little pictures from manufacturers so many professionals still get it wrong.

KC_Jones

To the OP for your reference and a perspective on how good it can be. I have a smaller version of your boiler and to know when mine is running I have to go into the basement to see if the burners are on. That's the way a proper steam system should be. It sounds like you are for sure sucking water out because of that piping. What is going to most likely happen is you are going to flood the boiler. All that make up and subsequent draining will destroy the boiler. Make up water brings oxygen, oxygen corrodes the boiler. Boiler corrodes too fast and gets a hole, now you are replacing again.

SWEI

You might consider offering a small carrot with the stick: Repipe it to manufacturer's specs at his expense, but you'll pay the difference in materials cost for increasing the pipe size.

A sketch of the proposed pipe layout posted here would be recommended.

Charlie from wmass

An EG 35 I just installed as reference. Dave Brunnel is one of the best and in your area.

Abracadabra

Took a look at @arbalest 's boiler today and I have the following report.

- Proper header needs to be built.
- Returns need to be dropped to floor and hartford loop properly piped. The bottom of the return manifold is right about at the nominal water level of the boiler. When the water level drops, there's the issue of live steam getting back into the returns from the "equalizer". I use equalizer loosely, but there's been a "equalizer" piped from the original "header" to the return.
- More main venting required.
- Makeup water supply needs a backflow preventer.
- Installation of a vaporstat and low pressure gauge (0-30" w.c.)
- I also suspect that boiler maybe be oversized as I was told that 30%?ish? was added to system EDR and a boiler with 130% of EDR was selected.
- I'm also not thrilled with the installation of the probe LWCO. I've always installed the probe type LWCOs directly into the tapping specified by the manufacturer. This installer created some kind of kludge manifold to get the probe LWCO installed away from the boiler. Looks like Hydrolevel lets you do that using a specially built tee, since I think the probe would bang into the side of the run of the tee. This IIRC was a MM probe LWCO, without any kind of special tee. Not sure if MM provides a shorter probe. Main LWCO is a MM#67 and the way it's installed it blocks the normal tapping provided on boiler. Has anyone installed a probe type LWCO not directly into a boiler tapping?

But pretty sure that main issue with hammering was due to the lack of skimming. It seems installer really did no significant skimming.

That's all I can remember off the top of my head.

Fred

I'm glad you were able to actually go over that system and let the Poster know exactly what needs to be done to correct this installation. Hopefully he can/will minimize future headaches for himself by getting those corrections made and then enjoying his steam again.

KC_Jones

Abracadabra said:

- I also suspect that boiler maybe be oversized as I was told that 30%?ish? was added to system EDR and a boiler with 130% of EDR was selected.

Am I the only one that goes crazy when I hear about this stuff? Is it really that hard to size a steam boiler? I mean seriously?! The toughest part is finding all the radiator sizes, after that (no offence against anyone) I could teach my 8 year old how to do it. I know there are bigger systems with other considerations etc., but on boilers this size why do people try and complicate it?

So is there any plan? Are you going to work on it now, or is this information now going to be presented to the original installer? That LWCO setup sounds odd at best.

Charlie from wmass

I am curious is the LWCO for a steam system? It sounds like a hot water one.

Fred

KC_Jones said:

Abracadabra said:

- I also suspect that boiler maybe be oversized as I was told that 30%?ish? was added to system EDR and a boiler with 130% of EDR was selected.

Am I the only one that goes crazy when I hear about this stuff? Is it really that hard to size a steam boiler? I mean seriously?! The toughest part is finding all the radiator sizes, after that (no offence against anyone) I could teach my 8 year old how to do it. I know there are bigger systems with other considerations etc., but on boilers this size why do people try and complicate it?

So is there any plan? Are you going to work on it now, or is this information now going to be presented to the original installer? That LWCO setup sounds odd at best.

Unfortunately adding another 30% for the pick-up/piping sounds like another indicator that the installer probably is not a Steam Pro.

Dave0176

arbalest said:

Dave0176 said:

It looks like you have one 2" riser coming from the boiler...

It is actually a 3" riser but I will pursue getting it redone with 2 of them. Thanks for the detailed information on the velocities and the effect it has on pushing out water. I can see this in action as this morning (when the thermostat first moved over the the morning schedule) the boiler started out with 1 minute cycles -- pausing to take in more water each time! After plenty of water was up there (5 cycles or so) the hammering started.

Ok well at least it's 3". I'll give you more numbers to check out. With a single 3" riser your steam is leaving at 37-38 feet per second or about 25-26 mph, two 3" risers cut velocity in half to about 18-19 feet per second or 12-12.5 mph. So that should put the speed into perspective. Issue that steam a speeding ticket lol.

Charlie from wmass

In all fairness until coming to the wall I always thought that adding 30% was required, and no one ever told me differently.

KC_Jones

I guess all we need to do is get EVERYONE to come here then? That shouldn't be too hard should it?

STEAM DOCTOR

Be careful when LWCO probe is not installed in boiler tapping. I have seen boilers where installer used a nipple and coupling. Boiler was on bit of tilt toward probe. Coupling and nipple were always filled with water because water doesn't flow uphill. LWCO never cut out. This is always why I don't like pressure relief valves on sides of boilers.