mixing black fittings and galvanized

kesslt

Hello,
I am a homeowner and we are having a new boiler getting installed today. After doing research, we specifically contracted to have the copper near boiler pipe replaced with black pipe. After the first day of work, we went down it it looks like they put in galvanized with cast iron fittings (on the steam / dry pipes). Is this okay? We raised this and they said galvanized is better because of the zinc coating to prevent corrosion and that they didn't ask to because it was an upgrade. Also, they said they couldn't get the black pipe and that's why they used something "better." I read that galvanized can flake in a steam system and clog things up - but the installer says that's not a problem in a steam system with relatively wide pipes. He said he'd be proud to have what he put in my house in his house and that the pipes will outlast the boiler. Also, it is of any relevance, the return is copper (keeping that from old system).

Any opinions about this? Should we insist that the galvanized pipe be removed and and replaced with black pipe?

Jamie Hall

Sloppy or lazy or cheap. Or all three. Galvanized is not better than black iron -- cast iron. Galvanized fittings will rust -- they're steel. So will cast iron -- but not as fast. Galvanized is usually less expensive, and yes, it is easier to get.

ethicalpaul

Add "ignorant" to your list @Jamie Hall

If I, a lowly homeowner, can buy malleable iron or cast iron fittings (and I can), then any contractor should be able to figure it out.

kesslt

Now that I pointed this out, the contractor says they will extend the labor warranty from 5 years to 10 and they will warranty the pipes for 20 years. (And they threw in a free sump pump). Still trying to decide if I should insist that they change it out and put in black pipe, It is a day of work. How important is the galvanized to the longevity of the system?

Jamie Hall

Well... the galvanized may last 20 years... maybe. Malleable or cast iron would last a century or two...

JUGHNE

IIRC, another concern with galv flaking that it could plug air vents, orifices and traps....no "wide" pipes involved in these.
It seems that black pipe would be more readily available than galv pipe.
Perhaps they got a good deal on some import galv piping, which IMO will not last as long as galv pipe of the 50-60's.

You probably could not insist on USA black pipe at this point. Most likely would end up with China blk pipe.

How much length could be involved unless they are re-piping the entire house?

mattmia2

Probably a great idea to open the installation manual and compare to the piping diagram at this point.

pecmsg

Where's this contractor getting his Material............
Home Cheepo, Blows?

Please post pictures!

kesslt

here are pictures - the job is supposed to be finished tomorrow.

Jamie Hall

oh dear

pecmsg

Jamie Hall said:

oh dear

Come On...............

At least its not copper!

kesslt

If you can be more specific it would help. I think they'd be open to feedback.

pecmsg

@kesslt
Where is this boiler being installed?

kesslt

In a residential basement.

pecmsg

kesslt said:

In a residential basement.

OK!

PC7060

pecmsg said:

In a residential basement.

OK!

I think @pecmsg was asking what locality not where in your house. Has a permit been pulled for the job?  Who is inspecting it?  

We should add “we’ve always done it this way” to the famous quotes thread. 

motoguy128

Why? Do they seriously not have a pipe supply house near them? Where did they order the boiler from? IF your going ot install steam boilers, you need to go buy some 3” pipe nipples. IN many cases you can return what you don’t use.

I had only been in this trade for 5 months when I ordered $500 Wotan of fittings and nipples from my local pipe supply to install my boiler. It’s not that hard.

Hell they could order them from Supplyhouse.com.

kesslt

Yes, a permit was pulled. Is there something specific I should tell the contractor based on the pictures? Thanks for your expertise if you can weigh in on the pipe materials or configuration.

JUGHNE

That type of side outlet boiler often wants full sized (no reducers at boiler) risers out of BOTH sides of the boiler. And perhaps a 2 1/2" or larger horizontal header. If they use both outlets one of them needs to be a Tee fitting so you can skim the boiler.
It is time to find the install manual and check piping diagrams included based on the model number posted on the side of the boiler.


For a correct installation they shall follow the instruction manual.
It is around there somewhere......maybe 50 pages or so.
(maybe someone took it home to study it for tomorrow's work....doubtful).

Those black fittings (90's and Tees) are considered malleable iron, (considered to be OK for steam use) not cast iron.
Up on the old piping are original black iron fittings, you can see a different thicker design.

I too have about that many galv nipples in my shop I would like to get rid of somewhere.

Even an old grey hair like myself could remove that galv set up in an hour....by myself. Those look to be precut store brought nipples....no cutting threading needed.
The horizontal header has too much slope (some is needed) for correct alinement to install a union to feed the right hand riser that goes up to the existing old steam main.

The correct configuration is to have: 1st boiler riser----2nd boiler riser (if needed)--- steam main take off---steam main take off---drop to equalizer/Hartford Loop (reduced on vertical drop only).

kesslt

Thank you, Jughne. They said it would be a whole day's work to switch out the galvanized and put in black pipe. The manual has two possible configurations - one with "one supply tapping" -- presume this means a riser -- and another picture with two. Our old boiler only had one riser and it's a small house so I assume we only need one riser. I guess if the angle is wrong they will figure that out when they try to "install a union to feed the right hand riser . . ." Anyway, if there is anything wrong that I should tell them to fix I'd appreciate knowing!

Intplm.

@kesslt .Go to your basement and look for the owner's manual. It might be down there. If it isn't, write down the make and model of the boiler, go to your computer, and download the owner's manual/directions. This way you will be able to ask better questions.
ie. How is this boiler going to be skimmed?

Please keep us informed as to how this all works out.

Jamie Hall

That boiler really should have two risers, as @JUGHNE said. The size of the house makes no difference at all. That said, you may possibly be able to get satisfactory performance with just one, provided that the riser is full size all the way up to the header and the header is at least one pipe size larger. And you skim the boiler and skim it again... and again... and again... until you are sick of it. And are really faithful at keeping the water level in it where it belongs; there's very little margin on that with just one riser in use.

JUGHNE

The install book covers all sizes of those boilers.
You have to find your exact model/size number and then refer to the piping required for that model.
These side pipers used to have 2 1/2" side outlets and you were to use that for the riser size...some lately have come with only 2" outlets. Perhaps they require a larger pipe size for the header.

So far all your pipe looks to be 2". Often the size is stamped on the edge of the fittings. Is that a reducing 90 on the right side of the boiler?, that is 2 1/2" x 2"?....I can't tell by the picture. A better shot would help.

If the book chart for your model/size of boiler states that 2 risers are optional then you may only get one out of this crew.
But most important is the SIZE stated for the risers and the horizontal header. (2 1/2" or 3" etc).

The size of the house does not matter for the boiler piping.
The main concern is the dryness of the steam which is dictated by the number of risers and pipe sizes of riser(s) and horizontal header. (this can cause grief for the life of the boiler).

kesslt

Hi - here's a better picture of the right side. Also, a picture of the installation
manual about how to do the piping with one riser.

EdTheHeaterMan

I can't help but notice the one riser is slightly tilted as mentioned earlier and within a 1/2" of the remaining section of the riser connected to the main. Both the bottom end of the upper pipe and the top end of the lower pipe have no threads. I'm wondering if the contractor plans to use a dresser coupling to make the final mismatched angle connection.

I don't think I would like that arrangement. No flexible couplings with rubber parts on steam. But that is my rule, I m not sure what the experts say, I only had about 15 Steam boiler accounts in my years of contracting. No Expert here, I have asked for advice here in the past.

EBEBRATT-Ed

I noticed the crooked riser at first I thought they welded it that way. but the piping wasn't finished so there is probably a leaking union there.

The sad thing is. Just read the manual. And it take no more work to screw it all up that to follow the MFG minimum piping requirements.

kesslt

They said there is asbestos above that pipe and that's why they used two shorter pipes on that riser - to avoid messing with the asbestos. There won't be any rubber or flexible materials joining those two pipes. Something about a high-pressure connector. We are supposed to have heat today.

Intplm.

Make sure they install a skimmer and skim this boiler. From the posted pictures, there is no skimmer installed.

Bomba

So, do you have heat ?

JUGHNE

The 2" nipple and cap on the opposite side of the boiler would work for skimming.
Again, a 2 x 1 1/4" reducing coupling may be needed to get the skimming water to float up above the top of all sections.
The push nipples across the top are usually much smaller than the side outlets.
Installer may not believe this, but a quick look inside the section push nipples will confirm the size reduction. IMO

EdTheHeaterMan

Mixing Blacks and Galvs can have so much influence on the children. My Daughter is a D.O. and my son-in-law is an M.D. My grandson is so confused, being from a mixed marriage. Be careful when mixing pipes.

kesslt

Hi Jughne - yes there is heat but the boiler definitely needs to be skimmed. Radiators are panting and water surging and radiators heating just halfway (not all fins). We asked for them to come back and skim. I will also ask about adding a reducing coupling. Question: what do you mean by "The push nipples across the top are usually much smaller than the side outlets. . . a quick look inside the section push nipples will confirm the size reduction." Is this the same thing as needing a reducing coupling or a separate issue from the skimming valve?

JUGHNE

When skimming you want the water to rise up in the boiler and float oils, etc off the top and out your horizontal drain.
By adding the reducer on the horizontal skim pipe you raise the water level higher inside the boiler. This insures that you are draining water that is coming up through all sections of the boiler and not just the one closest to the side opening.
The connecting nipples inside the boiler are smaller than the 2" side port, so as you drain off water only the closest section will drain off.
The other sections will just hold the water as the level will not come up over the reduced internal nipple openings. The bottom of the small internal nipples are higher than the bottom of side drain.

I noticed this on an older boiler of this design when getting the 2 1/2" plug out of the tee, looking inside at the push nipples between sections, even 1 1/2" pipe would not fit inside the openings.
Maybe the design has changed since then, but I doubt it.
This is a reason that these side connected boilers work better with both side outlets connected to the header.
With just one riser, then all the steam has to pass across the reduced size nipples and struggle to get out of the boiler. IMO

kesslt

Thanks for the clarification. Too late now they are not going to add a second riser. I will ask about adding the reducer though.

ethicalpaul

The shortage in the trades must be heavy indeed when contractors can dictate to the homeowner what materials they will deign to use and which connections they will choose to utilize.

Gilmorrie

Common black and galvanized steel pipe is the same ASTM A53 steel (not iron) pipe - except for the galvanizing. For hydronic heating systems, there is no reason they can't be mixed - but black pipe is preferred because it is less expensive. For natural gas piping, black, ungalvanized is preferred.

SlowYourRoll

you can see my other post earlier today in this thread (https://forum.heatinghelp.com/discussion/182618/cleaning-corrosion-good-idea), but long story short you don't want to be pairing galvanized with iron or other steels in terms of galvanic corrosion. you can see for yourself on this chart (galvanic steel would be under "zinc and alloys" in the table): https://www.grabberman.com/Media/TechnicalData/127.pdf

kesslt

Thanks SlowYourRoll. Here's a chart discussing the compatibility of fittings with galvanized: https://www.engineersedge.com/hardware/fastener_material_galvanic_13354.htm. It says that corrosion risk is "marginally increased." (I am told that the fittings they used (in the picture above) are malleable iron). So is this terrible? How fast will the corrosion take? The saying it is okay and that the piping will outlast the boiler. How many hours of work woudl it take to replace those galvanized pieces?

SlowYourRoll

kesslt said:

Thanks SlowYourRoll. Here's a chart discussing the compatibility of fittings with galvanized: https://www.engineersedge.com/hardware/fastener_material_galvanic_13354.htm. It says that corrosion risk is "marginally increased." (I am told that the fittings they used (in the picture above) are malleable iron). So is this terrible? How fast will the corrosion take? The saying it is okay and that the piping will outlast the boiler. How many hours of work woudl it take to replace those galvanized pieces?

that chart is for pairing bolts and base metals, so i would use the more generic chart from that site for this ( https://www.engineersedge.com/galvanic_capatability.htm ). this chart is the way we did this in school. it states that you want to keep the voltage drop between the two metals to 0.15V for harsh environments and 0.25V for normal environments. the anodic index of galvanized steel is 1.2 and the index for malleable iron is 0.85, so 1.2-0.85 gives you a voltage drop of 0.35V, which is too high for either cutoff.

as far as what to do now and how many hours it would take, you'd need to get someone else on here to advise you, cause i'm just an engineer not a plumber. if the pipes can be adequately isolated from each other electrically then that breaks the electric circuit and GC can't happen, but you'd need an experienced plumber to tell you if teflon tape and pipe paste is enough to do that. they sell dielectric (i.e. electrically insulating) unions and fittings (https://supplyhouse.com/Dielectric-Unions-and-Nipples-1640000), so the fact that product even exists makes me suspect that teflon tape alone might not do the trick, but again i have zero hands-on experience of it, so someone else would need to comment on that. sorry i can't be of more help, but better for me to know my place than give you bad/unnecessary advice.