Plumbing near boiler piping: need short custom nipples in black pipe
Novice here, replacing my boiler with an identical one (Weil-McLain WGO-3). New one is coming next week. Want to have as many ducks in a row ahead of time as possible, as I've never replaced a boiler before and even with advance planning everything will take 872 times the time that it would take you to do it, plus I will be confused, break something, etc., all with cold weather here or coming.
I would like to mimic the old near boiler piping almost exactly (that was part of the idea in getting an identical one, easier on my novice skills). To do this the most critical part would be getting the exact length of two particular black iron nipples right, the first two horizontal ones out of the return tapping, so that the lower part of the return riser mates up exactly with the 1-1/4" pipe coming straight down out of a 4-zone manifold way above (no way I can move that manifold to meet an errant riser). For the vertical part of the riser it's not as critical to have the vertical nipple lengths exactly right (although it would be nice), because I could compensate by lengthening or shortening the nice easier-to-work-with copper top part of the riser. (More text after photos.)
(The new circulator may or may not get moved to the supply side, I guess if it does I'd replace it on the return side with a union and longer nipple.)
I know from my recent plumbing classes that threaded iron and brass pipe is a lot less forgiving dimension-wise than 1/2" copper, which often you can kind of bend and coax to your will, at least the smaller stuff. That's why I feel I need to get those first two horizontal nipples exactly right.
I will go under the assumption that the current nipples are not a standard size. I figure my options are:
- Buy the closest standard size nipples ahead of time. Once I get the new boiler up on the blocks (which I do not look forward to doing, BTW, it’s a 600 lb boiler), slap them in and hope. But if that makes the riser askew, I'm back to square one.
- Measure the old installed nipples now and estimate their length (I guess by adding 2x the makeup/thread engagement length, which I'd get from a chart, to the length from the face of the boiler to the face of the first elbow, for the first nipple, similarly for the second). Then have Home Depot cut and thread them, if they can do it (which is not clear, the guy on the phone waffled as to whether they can cut a 3" or shorter nipple, at first he said no, they don't have a nipple chuck for the machine, then he said they have a way to do it without the chuck but I didn't understand the way and don't have confidence…) If that worked, great, but if it then it wasn't an exact fit I'd have to run back to HD (with a disconnected system) and then of course the guy who does the cutting will have called in sick or the machine broke or they ran out of 1-1/2" and 1-1/4" pipe.
- This is what I'm guessing you guys do: After getting the old boiler off and the new one up, remove the old nipples and measure them for an exact length and cut and thread them on site. Then even if once you put them in it's screwed up for whatever reason (Chinese fittings, weird threads, etc.) you can redo it right there until it's right. Now I don't have the tools but I can buy them (no rentals around here that I've found): cheapo pipe threading tool with dies plus a cheaper Doyle tripod chain vise (I don't have a workbench) at Harbor Freight would run about $300 total. This is unappealing in that it's $300 for a few $5.00 nipples, and I'm not sure I'd ever use the tools again. But it's also appealing, because it's tools and I can always tell myself that I could turn around and sell them on Facebook Marketplace as 'used once' although I won't of course but most of all because any such tools, even $300-and-maybe-never-used-again tools, would still be a drop in the bucket compared to the many thousands I'm saving if I can do this install myself. (Obviously I have no plumbing HVAC acquaintances close enough to borrow their stuff.) But to do this I have to ask a question, and I will put it in italics because if nothing else I need an answer to this one: If I buy a tripod chain vise and manual ratcheting threading tool, how can I cut an approx. 3" nipple, or maybe a little shorter? I assume that's too short for the chain to hold and have enough clearance to thread. (I don't have a chain vise here to check.) I read you can use a "thread protector," first cutting threads on one end of your pipe, cutting off the short length, so now you have a 3" or whatever length of pipe with threads on one end. Then you cut threads on one end of the longer leftover pipe, and thread that into one end of the thread protector.. Then you thread the short future nipple into the other side of the thread protector, so now you basically have a longer pipe to strap in. After you thread the other end of your nipple which is now sticking out of the thread protector, you screw it out. The thing is, after a quick look online it seems that metal thread protectors are few and far between and maybe expensive, especially in 1-1/2" and 1-1/4". Could I use a regular 1-1/2" (and 1-1/4") threaded coupling? The thing about that is, I read that the thread protector is straight, not tapered threads, which would make it easier to get the nipple in and out. With the coupler the taper would mash it in tight and might mess up the threads and/or make it difficult to remove. So in general how do you guys thread short nipples manually?
- Another possible method occurs to me. It might even be by far the best because if it works there's no pipe threading at all and the measurements don't have to be as exact: For the two critical horizontal nipples, I just buy two standard size ones a few inches too big. As a result, the bottom half of the supply riser will miss the top half significantly, but then with two 45 deg elbows I can solder in a 45 deg offset (in the easier-to-work-with copper pipe upper part of the riser) that mates the two. It won't be as nice looking as a straight run up or down, but no tool expense for threading (even though I'd like the practice).
I'm VERY curious as to what you pros, walking in on this basic situation, would do.
(I know some of you looking at the pictures will have all kinds of ideas and suggestions of things to add and change when the new boiler goes in, and of course I welcome these, in fact depend on them, but also please try to answer the specific stuff above.)
Comments
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Do you have a picture of what you're trying to do? There is some wiggle room in black iron pipe and if you are connecting between different parts of the boiler you need a swing joint which will give you more wiggle room in addition to keeping the expansion and contraction from pulling the boiler apart. the half inch increments black iron nipples come in is enough to fit anything up, there is variability in how much it threads in to the fitting and you can use that to your advantage by intentionally threading it in more or less. but mainly expansion and contraction means you need to design for some wiggle room anyhow.
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I assume this is hot water since you're talking about copper.
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If your concerned about the nipples coming out of the boiler for the return they will be standard size.
Nipples are available in 1/2 in increments from close-6" and in 1" increments from 6 1/2"-12". If you need something longer to avoid cutting your own nipples you can often use a coupling and 2 standard nipples.
In addition some supply houses can cut nipples as well as the BIG BOX stores can but their qualtity is sometimes suspect.
Nipples for 1 1/4, 1 1/2 and 2 " pipe will usually thread in about 5/8-3/4 of an inch on each end with some variation.
Since it is hot water you could always use copper tubing and fitting. But come out of the boiler with a nipple and an elbow or coupling.
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@mattmia2, regarding that variability and intentionally threading it in more or less, my (novice and surely false) instinct tells me that either anything short of jamming it in to the max, or backing it off after jamming it, might cause it to leak? Maybe not? Also, is it a thing, if you need a little extra length, to use more teflon tape so it gets tighter quicker?
The way those elbows and nipples are in the middle picture, at the bottom of the return, would that by any chance constitute a swing joint?
@EBEBRATT-Ed tomorrow I’ll measure the nipples and add the 2x the fractions to see if what’s in there is standard. It does make total sense that it would be. I did that yesterday and at least the longer one came out to be 4”, so standard. The shorter 1-1/2” one I can’t remember. If for some reason standard ones still caused the lower riser to be out of shack, I guess I could be prepared to go with a plan B of overlong nipples and 45 degree offset up top. But from what you guys are saying, it should work with the closest standard sizes and custom cut shouldn’t be needed, saving me a good bit of expense and work.
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Everything there looks like it will move an inch or 2 without a problem. You might need to move a hanger or 2. try to pick lengths where stuff ends up level and plumb and square but that is really mostly for looks. the current install isn't terrible but is a little hackey especially around the prv.
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Detroit Nipple Works.
They ship. They respect DIYers,
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@mattmia2 , @EBEBRATT-Ed , and @Revenant I'm feeling pretty good about this; even though everything's still hooked up, I grabbed the 1-1/4" pipe that goes between the zones down to the circulator and could move it and the whole zone assembly maybe 1/8" or more in all directions. This play will hopefully help me. Either way, I'll find out the hard way.
I'm planning on putting the circulator in the same place. I believe that would mean that technically it's still "pumping away" from the expansion tank, which is what counts. I've read that it's still not ideal to have the circ on the return side, but not because it's not pumping away from the tank, but because that adds pressure to the boiler; the boiler can certainly take it, but in a pinch with higher pressure might set off the relief valve or cause it to leak. Opinions welcome.
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In a residential system with low head pressure, it is unlikely that the pump pressure would cause the relief valve to leak or open.
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The old nipples on the return look like they are not leaking at all. Why not use them? You can probably just spin all three out as one assembly by opening the burner door.
You can probably use the same nipple on the supply pipe also. You just may need a 18" pipe wrench with a 36" long pipe to got over the handle. that is the idea of doint a "Push-Pull" job. You use all the old parts.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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Use copper with sweated fittings.
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If you look at his post with the leak it is leaking between sections by the supply tapping but the supply nipple is pretty rusty from that so that should be replaced.
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@EdTheHeaterMan as always you have saved the day. That would seem like exactly the best solution. My guess (from lack of experience) would have been to look at those old rusty nipples and assume that either I couldn't get them out, or that I could but they'd break in the process, or I could but the threads would be all horrible and maybe rusty too. But when I think about it, those threads have been tight and unmoving and probably moisture free, even if for 22 years. Now I'm guessing that many times you may have removed nipples that looked old and rusty on the outside, only to find a usable (maybe even shiny…) set of threads? In other words, I'm hoping that removing a rusty nipple is not as dicey as a rusty bolt…..
What I may do is order those two horizontal nipples and an elbow or two in the standard size that I estimate is closest to what's in there now, because I notice that those black iron fittings are cheap. That way if something goes wrong when I try to remove the old ones, I have a backup on hand. If nothing goes wrong, I just spent $30 or less on insurance. If I were doing this for profit that would eat into my margin, but in my situation that $30 is less than 1% of what I'm hoping I'll save on labor and markup.
I do have a 24" pipe wrench to use for this, which is the biggest thing I own.
@PC7060 thanks, that raises a question: The piping is black iron up to the circulator, and I assume threaded brass thereafter to the 1-1/4" copper riser, and now we're in sweating territory. How far out from the return tapping can a person start to use regular copper tubing and sweating instead of threaded iron or brass? Clearly whatever goes into the circulator flange has to be threaded — but wait, I think they even make sweated circ. flanges:
https://www.supplyhouse.com/Taco-SFL-075S-3-4-Sweat-Shut-Off-Freedom-Swivel-Flange-Set-Lead-Free?utm_source=google_ad&utm_medium=Shopping&utm_campaign=Shopping_X_Plumbing_X_SSC_ClassA&gad_source=1&gclid=Cj0KCQiA57G5BhDUARIsACgCYnxe5EN2KTBVkpvug85ZugGnbKCFgAHH2ES6QBtxMz5YkO8N_cS1-U0aAnFzEALw_wcB
Is there any rule? It seems to me that copper tubing gives so much more flexibility since, as I'm learning, you can always cut and lengthen or shorten using slip joints. I do know that right at the tapping people will say black iron provides support for all that heavy stuff on the return line (although I've also read that technically you shouldn't have weight on it, but use hangers, but that's a whole other deal…).
@mattmia2 good point, maybe I'll have a nipple ready for the supply, too. Does it matter if that one is iron or brass? I'm hoping I can use the old one if it's not a standard size, as you can see there's little space to shorten or lengthen above the union. (Also I am debating whether or not to get a new 1-1/2" union, the old one might be still good.)
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No rule, just need to make sure the pipes are supported as required. The pump flange with shutoffs are nice. You may want to consider one with drains; https://www.supplyhouse.com/Bluefin-IFTHR075-3-4-Threaded-Isolation-Flange-w-Hose-Drain-and-Rotating-Flange
You can also use threaded flanges using 3/4-in SWT x 3/4-in MIP Copper Male Adapter (https://www.supplyhouse.com/Elkhart-30330-3-4-Copper-x-Male-Adapter)
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@PC7060 thanks. So many decisions ….
One thing that still boggles my mind is figuring out what order to assemble things. It seems to me I've gotten in jams, mostly with threaded stuff. Like, you can't always just go in a straight line from beginning to end, with, say, at the end a coupling then a nipple then another coupling; there's no way to turn the nipple so it goes in both couplings! I guess unions are what makes it all possible….
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I tend to switch from iron to copper pretty quickly. ProPress makes things go quickly but sweated copper is very cost effective for DIY and arguably a superior joint.
Milwaukee M12 tube cutter is very helpful as well.
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@PC7060 nice. Nice electric cutter too.
I’m wondering whether with threaded pipe you just work towards the union. Like if the union’s in the middle you just assemble from both sides going towards union. If it’s at the end you work towards that. Every situation must be different though.
BTW, I forget what that angled thing is going into the tee (photo below). Is that something I should replace on principle while everything’s apart?
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that is called a swing check. It’s a check valve that must be properly positioned because gravity closes the valve. If you put it in upside down, gravity will hold it open so then it is no longer a check valve.
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
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You work toward the union or flange or sweated or pressed or flare or compression connection but you need to think about where you have room to turn fittings. Sometimes the only way have clearance to screw a connection of fittings together is before you connect them to the further from the union connection. It is also a lot easier to subassemble some parts in a vise on a bench then add the assembly in a lot of cases, you just have to think about if there is room to screw that assembly on. It helps to screw parts together hand tight to figure out how they have to be assembled and lengths of parts.
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Oh you are killing me with your overthinking. KISS - Keep It Simple Stupid
Cut where shown (and any other places that I can't see in your picture, pull the entire thing out of the way, put the new boiler in place, use standard length nipples where circled, and join your copper back together using sweat couplings.
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@mattmia2 that was very helpful, it gives me a framework. That kind of stuff just doesn't seem to be in books or even on the internet, or so I've seen. Comes from experience I guess. It took me a while to realize some of the strengths/weaknesses of threaded vs sweated, for example now I see why in some situations it makes sense to switch to copper like @PC7060 said, that in sweating some things are just easier, for example putting on a fitting like an elbow where there is no clearance to twist it if its threaded, with sweating you can just slip it on without twisting, and solder it. I guess maybe I kind of knew that but I didn't really see it clearly until now.
@MikeAmann, I'm starting to think I am really underthinking, and letting you guys do all the thinking for me. Your picture with the cuts is very helpful. @EdTheHeaterMan also suggested making cuts in the manifold. You will laugh when I say why I didn't like the idea of doing that, it really shows my low plumbing I.Q.: I did not like the idea of lifting that unwieldy manifold and maybe having to hang it with a hanger of just the right length or having someone hold it while I soldered the first slip joint on. Then looking at your picture it dawned on me: Idiot, I said to myself, once the new boiler is in place you just reattach the now loose manifold to the boiler via union or circulator flange which will easily support the weight of the manifold while I cut things exactly up top of it and solder slip joints at my leisure. Kind of hilarious how that did not occur to me until now.
If I go with the just the circulator and not a microbubble air thing (which would add an additional 6 inches added to the circ’s 8), it will still mean raising the manifold anywhere from about 4 to 8 inches (depending whether I also lower the boiler by having fewer blocks below it). But because the distance between the zone valves and those 45 deg. offsets above them may be less than this, I'll have to take out 3 or 4 inches below the 45's, and a few above them. So I guess for each pipe I'd make one cut just above the zone valve and another high above the 45's, remove that little assembly with the 45's, and when the shortened manifold is mounted back up hold that 45 assembly back up in the now shortened gap and mark exactly where to cut, then sweat on with slip joints (total of 8 slip joint plus one on the 1-1/4" pipe).
An experienced plumber wouldn't even be thinking about this, he'd walk up and take one look and just do it. But I'm not there yet.
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Now you got it! 👍️
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watch a couple YouTube videos on soldering copper and practiced a few. It’s one of those things that pretty simple once you get the hang of it and you shouldn’t over think it.
I’m out of touch with soldering after using ProPress for several years so I tend to overheat the joint. I’m sure @Mad Dog_2 can solder a joint in about the time it takes me to press it.2 -
The prep is everything. Clean, flux, assemble, and heat the joint not the solder. The solder flows towards the heat. When the joint is filled, you're done. Don't forget to wipe the flux off afterwards unless you want green corroded joints down the road.
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there should be a backflow preventer before the fill valve. A swing check, if that is the only protection, is not adequate.
At the very least a dual check 1024 upstream. Some inspectors accept a non vented 1024 dual check on plain water fill boilers.Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
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Thanks @hot_rod. Supplyhouse doesn’t have that 3048 model in stock in 1/2 inch sweat so I’d order it to put in at some later time. Apparently I’ve gone 30 years without one, so another month or two wouldn’t matter…
They do have the 573 with atmospheric vent in stock. Would that be as good or better? But then I’d have to have a discharge pipe to the floor?
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I would replace the entire assembly, fill valve and BFD. Yes the vent port should be piped to the floor. Although you rarely see that in the real world. A piece of 1/2” Pex is adequate for the discharge pipe.
There is a chance it will spit or dribble some day, you want that water on the ground not your equipment.
Many installers prefer to leave the valve turned off. The 573 also has a check in the discharge of the fill valve, so it would be shut off from system fluid and incoming water, in that case.
I would always leave the fill valve on for a few days or a week to be sure any air that vents out is replaced with water
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream1 -
Note that a lot of the "out of stock" supplyhouse.com stuff is just stuff they don't stock but get from the distributor in like a day. I have found most of the long lead times with out of stock status to actually only be a couple days.
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you can dry fit it first, screw it together hand tight to figure out what order it has to go together in. i try not to use close nipples because you can't remove them without an inside pipe wrench or something. they are also a little bit weaker.
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