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Flow Check install on multi-circulator parallel zoned system

Hi everyone,

I'm new to posting here, but have lurked for a few years, and while I see a great deal of discussion about flow checks, ghost flow, and thermosiphoning, it seems that there are varying answers---and I get it, each system has it's own peculiarities.

I'm updating my current multi-circ parallel zoned system to what I've attached (pulled from Siggy's Modern Hydronics, which I've read a few times). I've got a Pure Pro Trio P4 w/ a Riello F5 burner, Crown MegaStor MS-53 indirect to run priority (3/4" loop), but am only utilizing 2 3/4" zones w/ baseboard fin-tube (off 4 zone 1 1/4" headers). The circs are Taco VT-2218 (not sure what mode I'll be using them in for the zones, but it will be set speed for indirect). The controls are Hydrostat 3250 plus & Honeywell AQ25042B (same thing as the Pure Pro Energy Mgr. Plus II setup).

I'm sorta stuck on whether or not I should use a separate Flow Check on the returns of the baseboard zones (specifically Taco 218-3 since I have a few new ones lying around) since the VT-2218's have IFC's.

Also, as in the picture, there's a Flow Check just upstream of the tie-in of the IWH return to the common piping, and I've got a Taco 221-6 to go there. The thing I'm wondering in regards to this flow check is if I can utilize BOTH inlet ports on it and use it as the tee into the common piping from the IWH return piping. Since the IWH circ will be the only circ operating in the system on a DHW call, it would seem that there would be no flow issues as the upstream return from the other zones wouldn't be flowing. I couldn't find any info on using both ports.

The physical layout of my system is very much like the picture in regards to the orientation of all piping. If I were to use the flow checks on the returns, I'd just turn my return header (1 piece, 4 port CI) horizontally for the flow check and then make the 90 turn upward where my purge/ball valve would be.

Any advice would be much appreciated.

Thanks,

Jason



Comments

  • hot_rod
    hot_rod Member Posts: 16,315
    The checks on or in the circs should be adequate. With P/S piping you would want them on both S&R.

    If you do want to include them, use some hydronic specific spring checks, they can go in a vertical line.

    The check at the boiler is needed.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Rich_49
    Rich_49 Member Posts: 2,692
    Resistance on these baseboard zones may come into play in a big way here . I suggest figuring out the heat loss of each zone being served by an individual VT2218 , then figure out the head loss of each of them . I have seen many frustrated contractors ( term used loosely) and homeowners wondering why their Delta T circ that is programmed for xx*f is allowing fluid to return only 3-8*f cooler .

    My go to fix has been to use a Caleffi 132 series Quick setter set to the maximum anticipated flow , more often than not I have used a 1/2" 132 QS on a 3/4" circuit . I have seen Deltas of 4* magically rise to 17* immediately after the addition of the quick setter .

    You could also use zone valves with one circ for heat . If the head is adequate you run little risk operating below the curve and flowing water that is doing no work . What I mean by this is simply trying to match the the flow to the heat loss . Like 1gpm for 10,000 BTUh or 1 gpm for 5,000 BTUh . Dependent upon which school you recognize

    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
  • please_reboot
    please_reboot Member Posts: 9
    @Rich -- you know, I realized that those 2218's might not have been the right fit for the system, but I got a deal on them I couldn't pass up. I figure if I need to end up using them on a set speed, I'm still making out. I had done a heat loss on each zone and head loss a few years back and I can't find the info, so it never hurts to do it again.
    I was thinking about zone valves. I have a taco VR1816, just don't have the zone valves.

    @hot rod -- the check at the boiler you say is needed, that's the one on the return that's in the picture? Do you think using the 2 inlet ports of the flow check at the tee of the indirect return and common piping return would be ok, or will the check just upstream of the indirect return accomplish the same thing? I guess I'm thinking about heat migration from the return of the indirect back to boiler, not the return risers of the baseboard zones, or am I over thinking this and don't really need to be concerned about the heat migration from indirect return to boiler because of the checks in all the circs?

    I'm a network engineer....I over think things.

    Thanks for the responses. I've been trying to educate myself on hydronic heating and the more I read, the less I realize I think I know. But that's the fun of it!
  • Rich_49
    Rich_49 Member Posts: 2,692
    Think about using the VR1816 for the DHW application . Using the 132 Quick Setters will allow you to use the Vt2218 (s) in Delta T mode and fine tune the SYSTEM for optimal performance . If you're willing to do the math and tinker during the first season of operation you can do really nice things with that system .

    Figure out required SWTs for the emitters you have . Fine tune each zone for comfort . Reduce boiler ignitions by using ODR and using your boiler and temp like a hedge fund . Use less fuel by putting the effort and time into it .

    We accomplished a 30+% savings for this woman a few years back with an oil system by changing pumps to a Delta T pump with zone valves and a few slight piping changes . Comfort levels increased and fuel consumption went way down .

    http://jbblog.flopro.taco-hvac.com/delta-t-dawn-2/
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
  • hot_rod
    hot_rod Member Posts: 16,315

    @Rich -- you know, I realized that those 2218's might not have been the right fit for the system, but I got a deal on them I couldn't pass up. I figure if I need to end up using them on a set speed, I'm still making out. I had done a heat loss on each zone and head loss a few years back and I can't find the info, so it never hurts to do it again.

    I was thinking about zone valves. I have a taco VR1816, just don't have the zone valves.



    @hot rod -- the check at the boiler you say is needed, that's the one on the return that's in the picture? Do you think using the 2 inlet ports of the flow check at the tee of the indirect return and common piping return would be ok, or will the check just upstream of the indirect return accomplish the same thing? I guess I'm thinking about heat migration from the return of the indirect back to boiler, not the return risers of the baseboard zones, or am I over thinking this and don't really need to be concerned about the heat migration from indirect return to boiler because of the checks in all the circs?



    I'm a network engineer....I over think things.



    Thanks for the responses. I've been trying to educate myself on hydronic heating and the more I read, the less I realize I think I know.

    Yes, any delta T will encourage heat transfer. If a hot indirect has a a path, any path to the cold boiler energy will slowly transfer.

    It is even possible to have flow in two directions in a pipe, hot travels in the center, cold around the outside. A tall vertical line is the most common way to see that. So checks on both S&R are not a bad idea.

    Spring checks, not swing checks. Swing checks are not usually a bubble tight seal, and they need a pressure differential to seal at all. In hydronics, when the circulator stops, pressure is the same on both sides, that is why swing checks leak thru.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream