Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

loop cad design attached 5 days left with free trial to amend any suggestions.

keyote Member Posts: 659
Guys I have only five days left on free trial with loop cad, some of you have criticized the design a bit, if i understood correctly it was the flow to head ratio that bothered you and the suggestion seemed to be to shorten loops.
i had first followed the direction to stay under 350' and then figured out a couple of the longest ones were causing higher head on lower floors which surprised my [though youve explained it shouldnt have], but anyway i had shortened some of them and got all under 300' before i posted the designs.
Since there are certain conditions that make further shortening a bit onerous I guess my question is how grave is the concern do i really have high head or is it more like you could get it lower? why does it matter if i can still use an alpha or vt2218 as a secondary pump or can i?

One difficulty is the historic building makes routing difficult as does the hardwood floor nailing over it. The other thing is i had sort of gotten it so each loop served a major room which i hoped to zone independently by using actuators, but if the concern is pretty serious i will spend some more time while i have access to loop cad.

The top floor is in stone as it is already built and the riser is in, i have a couple caps on that manifold for a possible future PH addition, so that riser i ran in 1" copper. I plugged in 1" on the other risers thinking bigger was less friction for this design ive poste but that may be a mistake i can change.
The other question i guess is does anything look off in these numbers loop cad seems to get a bit buggy and throw strange numbers in places for a while then mysteriously clear it self up after youve given up rying to figure it out.

For those of you not familiar with my project [as if i haven't monopolized all of your your time this month ] Its a used TT110 mod con for now with 30 gallon buffer tank and a smart 50 indirect piped pumped as its own zone.
And i hope to use an ecm pump as the secondary with zone valves on the risers and actuators on the loops. [hope thats not making anyone laugh]
The lower floors are still under construction but i am rushing to get this boiler system finished before my tenants on the top floor discover they rented in a building with no heat lol. Theres an old atmospheric dragon with huge asbestos arms in the rest of the house for now.

To be honest although i drew the building very accurately i did not really know what to aim for in the design except generally so i may not have prioritized what i should have. i used delta t 10, but after that my priority was floor temp because its 85% hardwood over home made warmboard, with baths and kitchen cement board and tile over the same homemade warmboard. except cellar which is currently and will likely remain a slab. So the flows, water temp, etc are all i think just what loop cad came up with within those two parameters and i really have no idea if that a good water temp or flow from a design POV.
in fact i read recently you either control by increasing temp or increasing flow but i have no idea which is appropriate for a radiant job like mine or even if i have chosen one or the other by some of the choices i made but im simply saying is putting the the head/ flow ratio aside a moment is the water temp and flow a reasonable is delta t 10 a good choice? well thanks in advance.
Thanks all for your patience and help


  • Gordy
    Gordy Member Posts: 9,514
    Combine zones, and get loops at more closely matched head losses.
  • keyote
    keyote Member Posts: 659
    Gordy just came from your replies to my other two comments. And so i now realize there no way in hell im ever using just one secondary pump and ZVs on the risers. but i have checked the alpha and VT curves and as designed cureently each riser individually is not only within those pumps curve but within their self adapt curves, which would make me think its less important to get my heads lower. If i fall within the pumps curves what other concerns are there? i am kind of near the cusp of the self adapt curves so i guess margin of error is one thing. I only question because its not that easy to route pipes in a 110 year old house. I even got intrigued by siggys book talking about radiant ceilings lol .However there are some changes i can make particularly the worst manifold is an easy fix.

    what do you think about alpha vs VT? at first i thought they were just different brands not types of pump are they both possibilities?

    The worst zone is actually the basement and honestly its going to be the last floor renovated and i was really just getting something into the loopcad program to get the heat calc i only used three loops there so that an easy fix. especially since its a slab routing the loops is not a problem. done.

    Top floors already built
    I have an idea for the main floor of somehow pulling a high temp radiator for the interior hallway which is really cold and im not sure radiant will suffice.but maybe just a really heavy loop its a slab so .. and which would allow me to do some changes on the two that go in and out of that hall
    the second floor i have played with doubt i can get much more there. but ill take a look again.

    Now when you say combine zones what do you mean?
    one manifold per floor one pump per riser/manifold agreed?

    a zone is whatever has the ability to make a call so your saying dont put so many actuators and tstats in, put several loops on one tstat., i suppose unless you put an entire floor /manifold /riser on one tstat you still have to use actuators, but wire the tstat to whichever loops actuators youre grouping together. and that could be re arranged in the panel if unsatisfactory later. [wireless tstas or future tstat pulls in case no biggie.]

    and you want this done to increase the smallest possible heat call because of modulating concerns and your dislike of buffers. Ok I get that,

    its kind of theoretical because ill need the buffer for now anyway with the half built system, as it is im going to hook up a copper baseboard loop in the basement just to draw down,
    i think i can flush the copper well enough to risk hooking up to new work.
    im puttin a strainer on the hot water loop so by the time i actually wire the lower floors ill likely have a 10-1 modcon so those zoning changes are only on paper for now.

    In real life I could combine the loops for each apts bedroom and living room. on one tstat its just some rooms have a lot of solarization and glazing and other almost none .but since i **** up and didnt pull tstat wire im using the honeywell redlinks and they have a wireless companion module that can go in a second location to either change the tstat location or average the tstat signal so ill do that and average the bed/living rms and each apt will be a zone of about 8500 btu I could even temporarily gang both apts until i get some more of the house on the system
    hey i really appreciate you efforts
  • Gordy
    Gordy Member Posts: 9,514
    Use an alpha for each floor. So a zone to the zones so to speak.

  • keyote
    keyote Member Posts: 659
  • Gordy
    Gordy Member Posts: 9,514
    The taco Viridian 1816 is a nice delta p ECM also. A bit more money.
  • keyote
    keyote Member Posts: 659
    thanks only a few dollars more do you have a preference? i dont want a delta T pump in this situation.

    So Gordy how does this work, the tstat commands the actuator [s] to open and the pump senses the pressure differential when the actuators are opening and closing and has learned or been told the flow they require, but the boiler takes care of water temp and delta t by reading the outdoor reset and a return water sensor ? Does the pump know or care which exact zone is opening or just maintains a certain pressure across all open zones and that keeps flow correct?
Sign In or Register to comment.


It looks like you're new here. If you want to get involved, click one of these buttons!