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Looking for threaded Monoflow tees....Boilerpro

Boilerpro_5
Boilerpro_5 Member Posts: 407
Anyone know any sources? I am putting in a monoflow system and would like to use black pipe to save on materials and time putting up hangers. I need 16 of the 1/2 inch branch and 4 of the 3/4.

Boilerpro

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Comments

  • Big Ed
    Big Ed Member Posts: 1,117
    If You Can't Find Them

    ...I have a feeling you would not. And if you do ,the price would off set your plans .You may want to look at reducing tees 1 1/4 x1x1/2 tee .Narrow the branch between the radiators to cause the pressure drop.

    good luck
  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    I was thinking that would be good.

    > ...I have a feeling you would not. And if you do

    > ,the price would off set your plans .You may want

    > to look at reducing tees 1 1/4 x1x1/2 tee

    > .Narrow the branch between the radiators to cause

    > the pressure drop.

    >

    > good luck





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  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    I was thinking that would be good way around them

    Does that work well? I wonder how the pressure drop compares? I have found a couple sources, but they were about twice as much as copper monoflows. I am using panel radiators below the main and some are pretty big...15,000 btu, so I want to make sure to get enough flow. I suppose I could just add a valve in between the tees.

    Boilerpro

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  • c.t.kay
    c.t.kay Member Posts: 85


    call tunstall associates and order some orifice plates. put them in the tee next to the threaded end of the next pipe.
  • Big Ed_3
    Big Ed_3 Member Posts: 170
    Sure Can

    They installed this system in the late 50's and early 60's right before baseboard loops became popular . Sure the vanturi design is better . The valve in the middle would do the same as the reducing tees but you can regulate but you can also over regulate . Panel radiators can and are piped in Europe as a home run set up from a common manifold and trv thermostats . A pressure by-pass is needed as not to dead end the circ and a outdoor reset is a plus . Pex and panel radiators are made for each other .
  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    Sounds like the way to go

    Maybe I'll just buy a bunch of reducing tees and 6 inch nipples to put between them and let yer rip. As long as its works, OK. This particular system will have an exposed, about 250 ft. long main that loops around the building. I bet using a divertor tee setup, as such, would save alot of installation time over a homerun setup and be nice and neat, especially when down feeding.

    Thanks for your input, and it will save me some bucks too!

    Biolerpro

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  • Uni R_3
    Uni R_3 Member Posts: 299
    I have a spare 1¼ x 1¼ x .3/4

    > Maybe I'll just buy a bunch of reducing tees and

    > 6 inch nipples to put between them and let yer

    > rip. As long as its works, OK. This particular

    > system will have an exposed, about 250 ft. long

    > main that loops around the building. I bet using

    > a divertor tee setup, as such, would save alot of

    > installation time over a homerun setup and be

    > nice and neat, especially when down

    > feeding.

    >

    > Thanks for your input, and it will

    > save me some bucks too!

    >

    > Biolerpro

    >

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    And I'd give you 19 more if you'd help me install a manifold and homerun everything so I could take them out. I've never seen a Cv rating for an open monoflo tee nor ways to calculate head loss in a system. I even ordered modern hydronics to help with figure this all out but it was not to be.
  • Uni R_3
    Uni R_3 Member Posts: 299
    monoflo monoflo

    I'm my absolutely amateur opinion, I think you'd be making a huge mistake trying to use reducing tees in place of monoflo tees. To me, it would be like building a conventional plane with flat wings. You could do it, but it would need a lot more motor and not fly very well.

    The beauty of the venturi fitting is that the flow through the mains draws water through the branches - the same principal as airfoils. I think that using reducing tees would cause a much higher headloss for the system - I just don't know how much.

    You see, one thing I've yet to see here on the Wall or anywhere else including Modern Hydronics is how to calculate the headloss of a monoflo system. You can't even find the Cv ratings for these fittings unless the tee is capped and that's kind of pointless.

    My instinctive feeling is that the difference in flow would be tremendous and you would lose the evenness of the heat and you'd need way more pump to move it. I really like monoflos but I don't think they have much purpose anymore with the advent of modulating condensing boilers which are now prevalent on the gas side and in 10 years or so might also be prevalent on the oil fired side.

    Because of the velocity needed for the venturis to work, the ΔT on these systems is always going to be less than ideal. And if you slow the flow, the branches will have unpredicable flow. This new system may not have a condensing boiler now, but the next one might be.

    From a service standpoint as well, I'd want to shy away from a monoflo system. Every branch has to get bled individually. No purging it all from the basement - instead you have to find every emitter and bleed room by room whenever refilling the system or chasing air gremlins.

    That said, I do have a spare Armstrong threaded 1.25 x 1.25 x 0.75" if you want and if you wanted to help me homerun everything in my home, I could free up about 20 of them for you!!! ;-) All 3/4" branches though. My condensing boiler would love a higher ΔT!

    I think they're a great system, but between the low ΔT issue and the need for individual branch bleeding, I'd really try and do manifolds and homeruns first. I'm really fond of the whole manifolded-homerun concept. A couple of tubes of PEX or PAP for each run, and everything can get balanced for flow in one spot -- purged as well.
  • Steamhead (in transit)
    Steamhead (in transit) Member Posts: 6,688
    How about

    making the 250-foot main into a huge primary loop, and taking rads or groups of rads off the main as secondary loops with their own individually-controlled circs?

    Dan's friends the Levi brothers did this and it worked great.

    P.S. Check your e-mail, BP.

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  • Big Ed_3
    Big Ed_3 Member Posts: 170
    Added Note

    Greater the space of the tees the better the flow up to the radiator...
  • way back when

    Way back when the circ pump became available... This 1920ish bldg had addition built on in the 40's. The addition zone loop piping was reduced between the tees at the length of thin tube radaitors (above the main) works like a charm... Questioned my late father about the system, he said that way they were doing it for awhile til the mono-flo fittings came along...
  • bob_50
    bob_50 Member Posts: 306
    You could

    put a circuit setter between the tees and another on the branch, that way you could measure and adjust exactly how much flow you have in each branch. If it was for myself I would pipe it two pipe reverse return. bob
    rvette454
  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    Good idea, but....

    The Panel rads are all equipped with TRV's, so there is no need for seperate pumps. Trying to keep it simple.

    Boilerpro

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  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    Service issues, etc

    This system is an overhead main with bottom feed panel rads, so the main will bleed all by itself and the panel rads would need to be bleed individually anyway. I sure do know what you mean with having to bleed multiple times branch circuits above the main.
    The system has a condensing boiler and I've designed it to have a high delta tee across the system to keep efficiencies up and most of the time the system will be in setback, so operating temps will be low.

    Boilerpro

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  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    Makes me think.....

    That this sort of parellels the invention of the steam trap....They figured out how to make sytems work without them (orifice valves) and then traps came along. The manufacturers could sell more parts for new systems and get alot of return work on service if they sold traps. EVeryone benefited except the customer.

    A little cyncical at times, I am

    Boilerpro

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  • Uni R_3
    Uni R_3 Member Posts: 299
    High ΔT, TRVs and monoflo -

    > This system is an overhead main with bottom feed

    > panel rads, so the main will bleed all by itself

    > and the panel rads would need to be bleed

    > individually anyway. I sure do know what you

    > mean with having to bleed multiple times branch

    > circuits above the main. The system has a

    > condensing boiler and I've designed it to have a

    > high delta tee across the system to keep

    > efficiencies up and most of the time the system

    > will be in setback, so operating temps will be

    > low.

    >

    > Boilerpro

    >

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    Here's my experience
  • Roll your own venturi tees...

    One of the copper fitting manufacturers makes a small funnel shaped venturri fitting that can be dropped into a tee run. THey make them in 1/2, 3/4, 1 and 1-1/4".

    When I set up my own 1 pipe system in my home, the centers of the S&R going to my panel radiators were 2" on center. The closest I could be with stacked tees was 2-1/2", so I "modified" the sweat fittings to allow a true 2" center, and installed the venturri fittings in both the inlet AND the outlet to compensate for the excess pressure drop thru the radiators. Works like a champ.

    The name of the maker just came to me. They're NIBCO.

    Somewhere around here I have a picture. I'll see if I can find it in the Eatherton Archives :=)

    EDIT: Couldn't find the actual picture, but found a drawing I'd generated for it. You could easily drop female fitting reducers into the ends of the tees and have what you need for under $10.00 each.

    PS, THese fittings ARE still available.

    PSS: Found the NIBCO catalog on line and made a picture of this page. Interesting fittings here...HR would have a FIELD day in his shop with some of these fittings :-)

    I can envision forks, handle bars, swing arms, ALL kinds of appurtenances..

    THe link is http://www.nibco.com/assets/coppercat.pdf

    ME
  • Uni R_3
    Uni R_3 Member Posts: 299
    Monoflo and ΔT

    What kind of ΔT are you expecting?
  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    Hmmmm...HHOw to make these work with steel...

    Need to do some thinkin'!

    Boilerpro

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  • Uni R_3
    Uni R_3 Member Posts: 299
    Seems impossible

    Sustained at design, I'd be impressed by any monoflo system that could exceed a ΔT of much more than 10°F. You also have the further issue of both having to send warmed water downwards and the fact you intend to use TRVs on the branches.

    Personally, I can't see how you could slow the flow of 1¼" piping enough for a ΔT of 30°F and still have enough velocity to force water down through the panels. My 150' 1¼" loop is pumped with a 15-58. On speed 2 it works fine - with 120' of HWBB at design, the ΔT is only around 8° or so. If I switch to LO speed the heat goes all whacky and only some branches get heat. The diverter tees just don't have enough GPM to divert.

    I'm not sure of the head on my system but I'll give a wide range. If a wide ΔT were possible with monoflo, it should be just a matter of slowing the flow by an amount like this or maybe even less. It needs a minimum flow. Ask our resident nuclear engineer about the ΔT on his monoflo system. Anyway, heres 3 columns, head, GPM-Medium, GPM-Low.

    Head' GPM-Med GPM-Low

    3.00 13.82 8.23

    5.24 10.96 5.10

    7.09 8.71 2.98 < my guess would be around here

    9.10 6.31 1.14

    For 1¼", 1 fps = 4.7gpm, 2fps = 9.3gpm, and 4fps = 19gpm, and I think a 0.75" circuit would get about 25% of the gpm.

    I have no idea how to calculate the headloss on a monoflo system and have never seen or heard of it being done so I'm only guessing based on the fact my velocity is probably closer to 1fps than 4fps, but if my ΔT of 8° is with a flow of 8.7 GPM, I'd need a flow much lower flow than even the low speed on a 15-58 to widen the ΔT a significant amount. It isn't that easy because the tees won't work without a modest GPM to create the venturi effect. If the flow can be easily handled with 1" or 3/4" piping, why should any flow need to go all the way through the branches?

    Another issue is if a TRV closes off supply and the mains get hot before the TRV reopens, that circuit may fail to reheat until it can heat up with the system as a whole. The cooler heavier water in a radiator that's been closed can actually plug that circuit - there isn't much force being exerted at each circuit, so the water will just squeeze through the tees on the mains - that's easier. Also, if enough TRVs are closed, the overall flow will slow enough from the additional head that the branches will get uneven heat.

    I'm not sure you appreciate what I'm saying or not so I'll stop here. But if you're short a tee, I have one.
  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    I can see your conderns....

    I too am using a 1 1/4 inch main, but the design load is much higher than yours and I'll be running the same gpm through the pipe. So the delta tee stretchs higher. Also the system is running full outdoor reset so the trvs are not going to close much, so I don't expect that the overall flow will drop much.

    Design Info for monoflow systems is available from Bell and Gosset. So if you really want to run the numbers, give them a call. I have all the design and pressure drop charts for Divertor tee systems and its rather interesting. There are definite design parameters set up by B & G for the systems.

    Boilerpro

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  • Easy...

    Fitting by female adapters in the runs and or branches, with the copper fittings in between. Then you can run BIP between the tees, as you wish. Nice thing about it is that you can set up wahtever your heart desires for the side branches, not confined to whatever the maker (B&G or TACO) has to offer. Also, in a real pinch, I've taken 3/4" fitting X 1/2" copper reducing couplings and cut the majority of the fitting off, stuck it deep into a tee and had that give excellent results for a 3/4" x 1/2" venturri tee.

    In fact, on the tees that I made for my system, I used the fitting reducer in the inlet because it appeared to be much "fatter" than the NIBCO fitting, and use the NIBCO fitting in the outlet tee.

    ME

    ME


  • Uni R, I am curious why you would want to increase the delta-T of your system. I wish I had a delta-T of only 8 degrees. Mine is 25 degrees on a 120 foot loop, 1 1/4 inch Taco venturi tee system with 20 cast iron radiators. Circulator is a B&G 100.

    The big delta-T causes uneven heating between the first and last radiators in the loop, especially with low water temperatures.
  • Weezbo
    Weezbo Member Posts: 6,232
    *~/:)

    i have a group of them:) when i bought them :) they were signifigantly less expensive:) they are looking like a pinner copper cone.

    Mark is saying "You Too can make a monoflo T" :)
  • Uni R_3
    Uni R_3 Member Posts: 299
    Mike

    My return temps approach 140 at design. If I could widen my ΔT, I could increase my efficiency with lower return temps. Unfortunately, if I try and slow the flow any, like yours, my heating system would lose its evenness.

    Sounds like you need more flow to overcome the system head pressure. Are any of your branches closed or airbound causing additional head pressure? I'm surprised to see a B&G 100 on a monoflo system with a ΔT that wide, but not surprised to hear that your system doesn't heat evenly. Did it at one time?
  • Delta-T and heat input

    I think the real reason that I have such a large delta T is that the boiler is putting 130K BTU/Hr into the loop. I have a feeling that you have a similar flow rate, but a much lower heat input.

    My system has always worked this way since it was originally installed in the 1950s. It actually works pretty well, but the boiler is WAY oversized for the heat loss. During the recent cold weather near design temps, actual heat loss based on measuring gas consumption is about 40K BTU/Hr. Boiler ran for a total of 6 hours on a 10 degree day! With a more reasonably sized boiler I would probably have a delta-T similar to yours!

    You would expect that this would be a very inefficient system but actually, heating costs are reasonable given the 3600 SF heated area and 1950s insulation and construction.
  • Uni R_3
    Uni R_3 Member Posts: 299
    Mike, you're a bad ΔT example! ;-)

    See below... This is getting too squished.
  • Uni R_3
    Uni R_3 Member Posts: 299
    Over here Mike K...

    You said the real reason that your boiler has such a wide ΔT is that it's 130K. I'd say that's only half of it.

    How many gallons does your system have in total? I'll bet 50 gallons or more? Add all the mass of the steel piping and cast iron rads to the weight of the water in your delivery mechanism and that's the reason for your high ΔT. You push off hard every cycle but never run steady state. I'll bet you shut down before the piping and rad temps all level out.

    I can easily get my ΔT over 30° but it's the equiv of flooring it from a red light rather than cruising at design day temps. With fin-tube, my system has probably got less than half the mass of yours, so within 3 to 5 minutes, the ΔT is coming down fast.

    With steady state conditions, the BTUs added by the boiler should just cover the heatloss of the rads that replace the heatloss of structure. Open all your windows and doors so that your boiler can run for half an hour or 45 minutes steady the next time it's cold. Once everything is up to steady temps, what's your steady state ΔT?

    Let's look at this a really simple way.

    I'm under typical winter temperatures right now. I just checked the ΔT at the boiler and it is 6°F. Here's the kicker. I checked several branches and their ΔTs were all around 12°F. That's double, but that's how monoflo works! The branches all use a fraction of the heat passing by on the mains. The heat is sent around the circuit faster than all of the branches can use it. That's what it does.

    What this tells me is that my monoflo system is returning water at least 6° higher than it needs to and it's 30° above design - so at design it would be even more and get me a long way below my current 140!!! I'm also aware that the branch ΔT is limited by the flow demands of the diverter tees to move heat evenly into and through the branches. With a manifold or 2 pipe system where the water must go through the emitter no matter how slowly the BTUs are sent, the ΔT could easily be higher. Since my branches already are at 12° with the current flow, I could probably see close to 20° steady state at normal winter temps instead of 6°. Don't you think that would be far more efficient than my current monoflo layout?

    I've always been a big monoflo fan but since I've installed a condensing boiler, I'm really doubting this as a good method for piping to emitters. Unfortunately in my case, the efficiency gains would never justify the expense of ripping the monoflo out.

    If I were starting with a clean slate to use with a condensing boiler as in the case of this post, a monoflo system would be my last choice. With a higher temp oil boiler, I'd have no qualms at all with using it.

    Anyway, I'm starting to feel like I'm the only one here with this viewpoint so I'll leave it at that.
  • Christian Egli_2
    Christian Egli_2 Member Posts: 812
    Home made does the trick, like the bedazzler

    Go for the full venturi effect, it doesn't destroy nearly as much of the system head as partially shut valves, that, just because you recapture the pressure drop sucking on the venturi exit side otherwise lost in a plain flow restriction.

    Home made, like ME says, is the easy way to go. I think the cool catalog features shown above are mostly meant for all-copper fittings, for use in black iron, here are combinations I think will work most easily (they have for us in the past, again like Mark said.

    Using the plain iron 1 1/4 threaded iron pipe and a plain reducing tee, obtain the plainest copper reduction sweat fitting that goes from 1 1/4 to 3/4 (or choose 1 instead of 3/4, for less venturi action) The nice conical shape makes a very nice venturi nozzle. ** Get the one that fits on the inside of a 1 1/4 copper tube, because the ID diameter are similar for both the copper and the iron; except for cleaning out the burr and the chamfer on the iron tube, you're good to go. Then all that remains is to solder or alternately braze the two together. You now have got your pipe with the nozzle solidly on the end. All that remains is to screw on the plain tee and go on with life.

    I imagine this will be more convenient to set up in your case because it does not depend on how close the two flow tees need to be back to back for the coned nozzles to hold each other together. (I am picturing your system with the take off dropping down at each end of the radiators, whatever few feet that is - don't know if this is accurate, but I see your monoflow tee individually sitting here and there around your loop)

    There is nothing wrong about gluing cooper to iron, this way nothing is left loose, and it doesn't even have to be internally leak proof..

    I think this cost will be hard to beat and if you really need to stay all ferrous, I'd be happy to look into machining some venturi made of steel, or whatever else you wish. Let me know if you do.

    Somewhere I know I have a picture of this, but... and pretty soon winter will be over, so who'll need heat anyways by the time I find the picture.

    I always love to read about your methods, thanks Boilerpro.

  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    You guys have already done the thinkin'

    > Need to do some thinkin'!

    >

    > Boilerpro

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  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    You guys have already done the thinkin'

    > Need to do some thinkin'!

    >

    > Boilerpro

    >

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  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    You guys have already done the thinkin'

    I think I'll try using a couple of 1 1/4 inch copper fitting reducers soldered into a short 1 1/4 inch nipple and then jsut screw on the tees. I never have likedFemale thread adaptors too much potential for leaks, I'd think. I try putting some together and report back.

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  • Yes, it's better down here!

    You're right! I am a bad example. My system is anything but typical, especially when compared to a modcon or a system that maintains constant boiler temperature.

    First of all, I have never seen the system reach steady state. Temp will continue to climb until either the thermostat is satisfied or it reaches high limit at 160F.

    It is a cold start system, so water starts out at say 80F and delta-T is about 0. As firing begins output temp starts to rise, but return remains constant as the thermal mass of the boiler becomes heated. Over the period of about 5 minutes, delta-T will continue to increase until it reaches the 25F value and stabilizes. Output and return will slowly rise with constant delta-T until the thermostat is satisfied. Because of the high thermal mass of the water and iron, it takes hours of constant firing to reach high limit. Typically, the thermostat will be satisfied when water reaches 120F, up to 160F when coming out of setback on cold mornings. Effectively it performs like an outdoor reset, modulating water temp on the basis of heat demand, which is probably why efficiency is not as low as one might think.

    If the system ever did reach steady state, where heat input equalled heat loss, I think the delta-T would still remain constant. Think of the delta-T in terms of two heat loads, the load of heating the thermal mass of the system and the load of the heat actually emitted to the rooms. Summed together, they have to equal the boiler output which remains relatively constant. When the system first starts, the total load is that of raising the temp of the mass, no heat is emitted to the rooms because the radiators are at room temp. As the water temp starts to rise, the radiators begin emitting heat to the room, leaving less boiler output to raise temp of the system thermal mass. Eventually the temp rises to the point where the radiators are emitting all of the boiler output and no additional heat remains to raise the temp of the system mass. We are now at steady state. During all this time, the flow rate has remained constant and so has the boiler output, so how can the delta-T across the boiler change?

    I see what you are saying about the delta-T across each radiator being 12F and across the boiler 6F. It seems that the larger flow in the main averages the delta-T in proportion to the fractional flows of the branches. In the end though, all that really matters is the heat input and the flow rate.

    No matter what the piping system, for a given heat input and flow rate the delta-T still is the same. The problem with the diverter tee system is that it does not work properly at the low flow rates necessary for a higher delta-T in a system like yours. So, as you say, it may not be the best choice if you want to maintain a high delta-T.

    I am not sure how much efficiency you would gain by increasing the delta-T. From what you said, at design you have a return temp of 140F. With a delta-T of 6F, you need an average temp of 143F to meet the heat loss. If you increased your delta-T to 20F, you would still need the average 143F. Now your return would be 133F, still not enough for condensing, but you would now have a boiler output of 153F, hotter than your original 146F. Even at lower temps, with a higher delta-T you will always have a higher boiler output temp than you would otherwise. So would the possibility of marginal condensing make up for running the boiler at a higher output temp?

    By the way, how do you get the Greek delta symbols in your postings? Sure beats typing "delta" all the time!!
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