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REMS Curvo

Gerald just finished up a boiler replacement job.  The old boiler was a Laars with a mixing valve for the radiant and Gerald installed a TT PE110 and he re-used the old Aqua-Mate indirect.

He likes using the Curvo for bending hard-drawn copper because it looks nice and saves time.  Another advantage is that there is less pressure drop.
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hourTwo btu/ per sq ft for degree difference for a slab


  • Brad White
    Brad White Member Posts: 2,393
    Salvador Dali was a Wallie?

    Reads like a diagram, that.

    I would assume lower pressure drop, it would be interesting to see that quantified. Ideal application for a VS circulator.

    Nice work!
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • Paul Pollets
    Paul Pollets Member Posts: 3,620

    Very sexy!!
  • tim smith
    tim smith Member Posts: 2,547
    Curvoland !!!!!

    Nice and neat although the amount of room they give us for our mechanicals I would never get away with but pretty cool. Tim
  • Boiler room space

    Tim: I'm with you on having to struggle with the architect for a decent size boiler room.  Often a huge house and they give you a closet.  We lucked out with this house which has an expansive four foot crawlspace.

    Gerald came to me in 1997 when he had just immigrated from Nicaragua.  He had limited practical experience, but I needed an apprentice and hired him.  It turned out that he had an affinity for anything mechanical and learned quickly, soon becoming a journeyman.  Ten years later, he bought my business.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hourTwo btu/ per sq ft for degree difference for a slab
  • scott markle_2
    scott markle_2 Member Posts: 611

    Thanks for posting these pics.

    The curvo is a very cool tool. Which model is your friend using? Are they as expensive as a propress tool?

    Am I deluded to believe there is something superior to 4 port mixing as opposed to closely spaced T's. Perhaps I am, because the only advantage I can see is if the boiler flow exceeds the system flow. In this situation water is forced to flow in both directions between the closely spaced T's. This amounts to the pumps fighting each-other a bit.

    For the most part this condition(boiler flow>system) should not exists, if it does the system may not have needed P/S in the first place. (especially with the TT)

    What's up with the indirect? Why does it have so many ports on the coil? (I do see a colliding current in the return T at the indirect.) Other than that the water must be very happy to flow through those pipes.
  • Brad White
    Brad White Member Posts: 2,393
    Closely Spaced Tees

    I see what you are saying, Scott, about closelyspacetees and the potential for the circulators fighting each other, but I do not worry about it, presuming that the main is properly sized.

    Nothing says the flow has to go in the same direction but it does jibe with our sense of social order I suppose.

    If you consider the core premise that the space between the tees has a negligible pressure drop and is sized for the largest circuit flow, the pressure drop is still negligible.

    If this were not the case and there was a measurable pressure drop, the effect or rather "lack of effect" on each circuit, would go away and each circuit would influence the other.

    The backwards flow is also necessary to effect a T-mix in the secondary branch; as an example, a primary main of 10 gpm and a secondary branch of 20 gpm will have two 10-gpm flow rates colliding as they enter the secondary branch. Which is what you want.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • MikeyB
    MikeyB Member Posts: 696
    edited March 2011
    Power Benders

    Rems is a real nice tool, and Rothenberger makes one its called the Robend 3000, both brands look like well made tools, anyone use the Robend 3000? Real nice work Gerald
  • Counterflow

    Thanks for the question, Scott and thanks Brad for explaining it so well.  I don't think I could have done a better job.

    That's the beauty of primary-secondary, i.e. the pumps don't really fight, they just learn to get along.  Reverse flow through the common piping is OK although Brad, do we really want a thermal mix happening because it will further reset the temperature of our "smart" boiler and second guess the reset ratio that we've carefully guided the boiler to obey?

    On this job, both pumps are close in size, but with the added pressure drop on the system side, I'd say there's some reverse flow. 

    Scott: I forget what I paid for the Curvo; it was probably 8 years ago.  I see they have a battery powered one now.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hourTwo btu/ per sq ft for degree difference for a slab
  • Brad White
    Brad White Member Posts: 2,393
    Counterflow and T-Mix

    Thanks for the kind words, Alan- it means a lot to me.

    As for the T-Mix, that only occurs when you have a higher secondary branch flow and that is not a common occurrence. Most of the time we branch off with a percentage of flow and head on downstream as we all know.

    You are right, I said it inelegantly when I stated, "that is what you want". More accurately, "that is what happens". 

    Here is an application I came up with  where this principle was put to use without control valves.  It is something we used for a tempering tank in a laboratory process application. It did not use a boiler, it used steam to make HW via a heat exchanger so high supply and low return temperatures were not a problem as it might be on a boiler.

    This was a simple two circuit injection system using a high temperature primary loop (say 180F) and a lower temperature secondary loop (say 140F and a 40 degree delta-T, returning at 100F).  I forget the actual temperatures and flows used, so these are just examples.

    So the primary, moving along at 10 gpm of 180F water sees the first tee and collides with 10 gpm of reverse flow at 100F return water, mixes and sends out 140F supply to the secondary circuit. What goes back to the primary circuit return is 10 gpm of 100F water, imposing an 80 degree system drop. 

    The secondary temperature iwas maintained by varying the secondary pump speed. So long as the secondary flow rate is above the primary flow rate, you have a T-Mix on the outgoing supply line.

    Drop the secondary flow below the primary, (say to 8 gpm secondary vs. 10 gpm primary, you will deliver the hotter primary temperature into the secondary circuit.

    The pump speed controller responded to immersion sensors in the water jacket. (This process was to control yeast fermentation then quench the process with high heat to pasteurize it.)

    So, not a common application (a bit obscure I admit!), but an example of higher secondary flow at lower temperatures.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    do we really want a thermal mix happening

    I guess it depends a lot on your controls. On my Ultra-3, that is piped primary-secondary, the temperature sensor is on the secondary loop (the one where the heat emitters are) on the way to the heating load. So any mixing that happens between the closely spaced Ts does not affect the heat supplied to the house. If too much cold from the returns mixes with the heat from the boiler, the boiler temperature will have to go up some, but that is automatic. The reset curve controls the temperature of the water as it starts around the supply side of the load loop, not the boiler loop.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,840
    A work of art...

    I like them Swoopy turns as Weesbo use to put it.

    The only thing that causes me heart burn is the bull headed tees. I know it makes sense from a visual point of view, but one of the first articles Siggy wrote had to do with why you shouldn't do bull headed tees. In fact, it use to be against the code, but the enforcers got so confused by P/S piping, that they threw the baby out with the wash.

    Although NOT recommended, it is no longer against the code to bull head tees.

    Remember, your ex brother in law could be involved as a part of this hydronic heating systems operation... Mine was wet, lazy and stupid. I will say no more...

    Good work Geraldo.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
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