Tough piping scenario

Tom_133

Gentlemen,
I have a bit of a quandary, I am called to a job to clean and inspect a boiler, while I am there I notice the system pump sounds like its going to give up the ghost any second and because this job is on the mtn in Stowe Vt I recommend swapping it and some other service friendly changes. As I look around the header I notice all 9 pumps have old style isolation flanges that don't work (screwdriver slot) and explain that if one pump goes down we have to drain quite a bit of the system to change it and in January that will be rough, he agrees and wants all pumps changed (currently they are installed with motor up, not good I will remedy that as well) and new Isolation flanges. I say excellent, then I notice radiant temps are at 165 I ask why he says dunno, I try to turn them down, no chance the manual mix valves are frozen. He now wants those replaced. Ok, ok, I'm getting to the question. After looking at the header a bit closer the installer has an 1 1/4 black iron primary, and 9 zones coming off that, he has each zone coming off tees every 12" and has run the whole thing in series, so the water is progressively cooling to each of the last zones, he has an 0010 as his system pump which is overkill, and 007's on each zone pointed into the header. Here is the question: I want to spin those pumps away from the header and pump into the zone, I worry though that because the header was done as poorly as it was that if I do and there is any ghost flow in other zones (which I am sure there will be) I will have to fight with that system for a while. Should I just upgrade the pumps and keep it the way it was so I don't fight this boiler all winter? I talked to owner he said do what I feel is right, I said fix the header. He doesn't want to go that way too expensive he's selling the house. Any ideas?

Rich_49

Is the 0010 a boiler pump or a system pump ? Can you draw the near boiler piping including 007s so we could get a better idea ?

Tom_133

here it is sorry for the lack of colors, this is just a rough sketch

Ironman

There's no way that will work correctly unless each descending zone was over-sized proportionately for the cooler water supplying it.
You could keep the current manifold (if sized correctly) for the supply, cap off the return taps and build a return manifold.

The attached diagram of a moose antler may be the easiest form of p/s parallel piping.

Rich_49

Tom , what type of boiler are we speaking of ? It looks as if those pumps are on what would be the returns pumping into the we'll call it the boiler loop , is that accurate ? The homeowner better hope the prospective buyers home inspector knows absolutely nothing about heating systems .

Tom_133

Bob, I know how to fix it properly, it's more of a hands are tied situation. Customer is willing to put some money into it but not a lot. I am 100% with your pic on how to do it and I would love to do it that way.

Rich, it's an old Smith oil fired. Yes those pumps are on the returns and according to the customer "it has worked for 14 years that way and all the other houses I've built were piped this way and all the other houses work fine as well". Thats a pretty tough argument to put up when that's the customers line of reasoning.

So, with that bit of knowledge, is the consensus that I spin the pumps and at least try to make it right or do you think that will cause a bigger mess? Im leaning toward leaving them pumping toward the header since it "worked for 14 years like that"

RobG

At this point I would suggest just replacing the pumps and leaving it as is. If you start making changes and not addressing the entire system you'll probably end up re-piping it anyway but on your dime.

Tom_133

Rob,

Do you think if I keep it the same I can use Grundfos Alpha's? Here in Vermont the Alpha's are only 80 bucks right now and it would save him some money on electricity. Though, I am thinking I can't use it, due to the piping the alpha will probably not work. That's my guess anyway, anyone else?

I think I will just swap Isolation flanges and keep same pumps, that way he saves money and at least he won't have to drain the system when he needs to change them as they go bad in the future.

RobG

If he is satisfied with the system the way it is I would not change anything but the pumps, apples for apples (ISO flanges won't change anything performance wise so that would be fine). I never like to own someone else's problem.

Don_197

I agree with rob......once you change a "performance" parameter.....you own it. Iso flanges and get the h ee double toothpicks outta there!

Rich_49

Mass is offering a 100.00 per pump rebate for ECM circs , is that how you are getting Alphas for 80.00 , in Vermont also ? Bumble Bees and the new 2218s are available in the NE area and qualify , that way you could lower the pressure in that whatever loop and gain a bit of performance in the zones along with some added efficincy out of the system .

Ironman

Tom said:

Bob, I know how to fix it properly, it's more of a hands are tied situation. Customer is willing to put some money into it but not a lot. I am 100% with your pic on how to do it and I would love to do it that way.

Rich, it's an old Smith oil fired. Yes those pumps are on the returns and according to the customer "it has worked for 14 years that way and all the other houses I've built were piped this way and all the other houses work fine as well". Thats a pretty tough argument to put up when that's the customers line of reasoning.

So, with that bit of knowledge, is the consensus that I spin the pumps and at least try to make it right or do you think that will cause a bigger mess? Im leaning toward leaving them pumping toward the header since it "worked for 14 years like that"

Tom,
I totally agree with Rob and the others: if you're not going to correct everything and be willing to own it, then I would not correct anything. Notice that I said "correct" - that's different than "repair". Replacing the pumps and flanges would be repairing.
I would just leave my sticker on the boiler and then when the new owner calls you because it doesn't work correctly you can tell him the truth: the previous owner was advised that the piping was wrong but he did not want to pay to have it corrected.

Tom_133

I am of the same thinking, my plan is to bring replacement pumps (just in case) swap Isolation flanges and run all the scenarios by the customer. Thanks guys I needed a good sounding board for this situation.

icesailor

There's a less involved fix for that. Run a new and separate return all the way to the last circulator. You don't tie in the end. That becomes the primary circuit. Then, take whichever you decide and create "Bridge Loops" and span across the primary supply loop. That way, all secondary loops get the same equal hot water, and all returning secondary water goes into the primary return. I'm not looking at the installation, There may be "issues", But that is a common piping arrangement for an application such as yours. Most wet rotor pumps can be set on their heads if the pressure is high enough.

If yo see it right, and your customer doesn't want to replace the world, it is an option he might go for. Its simple and it works.

In my experience.

icesailor

If you or anyone else cares, here's how it works.

Say that the main that is run around to connect all those circulators and zones is 2" pipe or tube. At the last take off, cap the end past the last tee. Run another line parallel to the first. If 1" IPS is large enough to handle each zone, create a "Bridge" across from the supply to the Return. On the bridge, you place 2 closely spaced tees on a 1" IPS bridge. You can leave one side connected to the existing, just connect the other side to the new return. The 2" becomes the primary side, with all the 1" Bridge Crossovers giving you the needed flow. Inside or on the "Bridge" you create the hydraulic connection where the secondary water mixes with the primary. Inside each and every Bridge in a mini supply and return. Make sure that you have the supply first on the bridge because otherwise, the supply, on the wrong side will see cooler return water while circulation. 4 or more 1" IPS pipes will equal or be greater than a 2" IPS pipe. You'll need a big boiler pump.

It really is effective and works quite well. It is a way to resolve the problem without trying to re-pipe the world. I tried to find a drawing of this on the Internets but I couldn't. Maybe someone has something.

icesailor

"" After looking at the header a bit closer the installer has an 1 1/4 black iron primary, and 9 zones coming off that, he has each zone coming off tees every 12" and has run the whole thing in series, so the water is progressively cooling to each of the last zones, he has an 0010 as his system pump which is overkill, and 007's on each zone pointed into the header. ""

My way makes every supply to any zone off the 1 1/4" main get straight, undiluted hot water supply water from the boilers. Then, without any major changes to the working system, each and every return feeds into the return of the boiler. Regardless of how high or low the return temperature is. If the mixer is on any one of the supply zones, it doesn't have to be moved. It is already connected. If I had some sort of a drawing application on this computer, I would draw it for you. It is so simple that it is stupid. Its how all multiple circuit Primary/Secondary systems should be piped. The "Bridge Loops" are part of the Primary side.

Every time I see some drawing or actual installation of a Primary/Secondary systems with Multiple closely spaced tees on the primary side, I think about how cold the last circuit/take off at the end of the line gets. The same reason that Mono-Flow systems were almost always split in half. So that the last radiator on the circuit was hot enough. And Series Looped baseboard that is too long will have much cooler water at the last emitter than the first one.

Its already 3/4 done for you.

How many times have I seen someone try to re-invent the wheel when it only needed air in the tire. Or a plug in a tubeless tire to plug the nail hole. Its always a lot harder to sell a complete re-do of something that needs attention. Its always easier to sell a fix for something that doesn't mean re-designing the world of Hydronics. You can even pre-pipe the entire added system before you make the changeover. While you're changing the terminally ill system pump, you can change all the returns over to the new return. You probably would only need to cap the end of the supply and connect to the return.

It matters not to me whether anyone sees the value. If one person sees that there is a better way to connect a Primary/Secondary system with multiple secondary's. here's a better way. I had an old book from a Seminar I went to that Dan was the featured speaker. Taco was a sponsor. They gave us an old book. The drawing was in it. I had another one from Peerless. It was in it too.

Those old dead guys were smart. I'm not dead yet (though).

Tom_133

Ice, I follow what your are saying and would really like to do it right, but as you know swapping pumps, flipping flow checks, swapping mixing valves (everything being IPS in glycol for 14 years) takes time. My estimate is a full day + parts = $$$ so for me to add another day to make it right would add more $$$. I want to offer to fix it for free if he paid parts just to know it's right, but I don't need the practice and the reality is I need to make money when I go to work. Thanks for your help.

icesailor

Tom said:

Ice, I follow what your are saying and would really like to do it right, but as you know swapping pumps, flipping flow checks, swapping mixing valves (everything being IPS in glycol for 14 years) takes time. My estimate is a full day + parts = $$$ so for me to add another day to make it right would add more $$$. I want to offer to fix it for free if he paid parts just to know it's right, but I don't need the practice and the reality is I need to make money when I go to work. Thanks for your help.

No, you still don't understand. You do not have to change or move a single item in the entire system. You are cutting the primary loop at the very last supply outlet to the secondary. Cutting the return side at the last return of the secondary side, and running a parallel return back to the boiler. In the return sections of the secondary side, they get capped at the primary supply loop and connected at the return, back to the boiler. All water entering the supply side is hot and undiluted. The return water is cooler and diluted. If you had the time, you can install the bridge loops. Otherwise, it becomes a parallel reverse return. And all the benefits.

That's how you drew it. In practice, they are never installed as drawn.

In my personal and unproven opinion, those P/S piping systems like you drew are just another bad form of a Monoflow System, with the last radiator or circuit getting the coolest water after mixing. The boiler will still pump out the same temperature water, and the return may be the same. Its just that if the design temperature for each secondary circuit is 170 degrees, every circuit will have 170 degree entering water. Makes a bad system that seems to be working, even better.

You have to do what you have to do and the owner will go for. But I'd be looking that thing over and taking measurements to see what the supply and return temperatures are. It could be a nice gravy job later on. If the circuits on the end are significantly lower, ask how those areas react when the system is really loaded up. I'll bet it is hard when it is really cold.

Tom_133

Ice, I am on the same page as you fully. The piping is not the same as drawn. It has two more high temp zones after the radiant loops. My original question was related more toward if I spun the pumps would it make it better at all, but after some comments that were in line with my thoughts I just kept it the same. At least now it's all serviceable.

The job is now done and it works, not nearly as good as it could but when he sells it for 1.2 million (asking price) maybe the next guy will be ready to make it right. Thanks all

icesailor

No, when he sells it for $1.2 Million, the new owner will get some hot shot "Expert" ("X" being an unknown quantity and "Spert" being a drip under pressure) will completely do over the working system to something that barely works at all. With the latest high efficiency equipment that cost far more to run than the older, less efficient equipment that was there already.

Been there, done that.

Tom_133

This is an old thread of mine, but if you have a minute or two here is the current fix. This is a separate customer and he had the same piping problem done by the same guy. I am 90% happy with the days progress and the build but there a couple things that are making me crazy.