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Going from copper series circuit to homerun with manifold and pex, advice needed!

omarvelous
omarvelous Member Posts: 11
edited December 2020 in Radiant Heating
Hello! First post! I appreciate any help!

I'm looking to upgrade my heating from a 3/4" copper series circuit, with fin tube baseboards, to a 5 zone homerun system, using a 5 port manifold and pex. All runs would be at most 80 ft from baseboard to the manifold (including baseboard lengths). The manifold would be 2 feet from boiler. It will be 3x 12' baseboards, and 2x 8' baseboards, and are all SlantFin Fine/Line 30A. Two of the 12' are located on the same floor as boiler, with the remainder located the floor above. My boiler is a Weil-McClein cga-25 series 2 (https://www.weil-mclain.com/products/cga-gas-boiler-series-2).

My supply is 3/4" copper from and to boiler now. I'm considering this manifold which has a 1" supply/return (https://www.supplyhouse.com/Uponor-Wirsbo-A2700502-5-Loop-1-Stainless-Steel-Radiant-Heat-Manifold-Assembly-w-Flow-Meter).

I have the following questions:
  • Would I need to upgrade my supply to 1" to/from the manifold? Or can I use 3/4"?
  • Would I need to run 3/4" pex from manifold to baseboards, or can I run 1/2" pex and just use a 1/2" to 3/4" to baseboards? (Pex-A - https://www.supplyhouse.com/Wirsbo-Uponor-A1260500-1-2-hePEX-plus-500-ft-coil)
  • Would I still need to add air vents to any of the baseboards?
  • Any other considerations I should take into place?
Appreciate your assistance?

Comments

  • SuperTech
    SuperTech Member Posts: 1,689
    Why would you want to do that? What kind of problem are you trying to solve by changing the piping? Is scrap copper bringing enough money at the junkyards to make this worthwhile? I would understand if you were changing to radiant heating, anything else could likely be remedied without such a radical change. Post some pictures of your current piping, maybe then I will understand your motivation. 
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,290
    Are you adding new baseboard or replacing the old baseboards with the same newer same size and lengths?

    If baseboards remain the same and it heats with 3/4" now then 3/4 is ok. 1/2" to the baseboards. Provide air vents at the baseboard or at the manifold
  • omarvelous
    omarvelous Member Posts: 11
    SuperTech said:

    Why would you want to do that? What kind of problem are you trying to solve by changing the piping? Is scrap copper bringing enough money at the junkyards to make this worthwhile? I would understand if you were changing to radiant heating, anything else could likely be remedied without such a radical change. Post some pictures of your current piping, maybe then I will understand your motivation. 

    Part of the problem is during a renovation, I ripped out most of the copper in the series (as well as baseboards), and installed electric forced air heaters in each room (big mistake). The problems were uneven heat distribution. I'm pretty sure mostly due to air in the system. While it was super easy to install, electric bills aren't as pretty. So the main issue is there is no system in place now. And instead of adding back the copper, especially in the same manner, I figured I'd rather run pex and install mutiple zones.

    Believe it or not, scrap copper had declined around the time I did it, about 2 years ago. I still have the longer copper runs in my backyard (was saving for a potential scrap copper art project? 🤪
    SuperTech
  • omarvelous
    omarvelous Member Posts: 11

    Are you adding new baseboard or replacing the old baseboards with the same newer same size and lengths?

    If baseboards remain the same and it heats with 3/4" now then 3/4 is ok. 1/2" to the baseboards. Provide air vents at the baseboard or at the manifold

    I only left one baseboard in place. So I will be most likely adding new baseboards, but those same lengths. I was considering Runtal Baseboard radiators, which are 1/2" in, and most likely wouldn't need to be as long as the SlantFins I suppose? Most likely going with SlantFins again.
  • SuperTech
    SuperTech Member Posts: 1,689
    Ok, I understand completely now. I'm glad you realized that forced air was a mistake. I suppose its too late to convince you to go with radiant heating. I don't know what you are using for a boiler,  but it is usually a good idea to avoid having too many small zones with their own thermostats. Perhaps panel radiators with thermostatic radiator valves could be used to control the comfort in each room? 
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,388
    edited December 2020
    This seems like a lot of work for adding or replacing some radiators. Are there any rooms that are not getting enough heat?

    It sounds like you have about 52 feet of element total (the part with the fins) and that is well within the capacity of a 3/4" pipe. the boiler is also properly sized to the amount of radiation connected to it. I can see no benefit to the "Home Run" system you are suggesting. The inexpensive 3/4" loop design is why Baseboard was invented. To keep things simple.

    If you want to reinvent the wheel Go for it! 1/2" Pex to each home run will work fine in your design. I'm guessing the building is not being used to park your Boeing 747, so there won't be that much difference in temperature from one room to the next either way you do it.

    Just be sure you leave a place to release or purge the air from the system. Especially the higher 2nd-floor areas
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
  • omarvelous
    omarvelous Member Posts: 11
    edited December 2020

    This seems like a lot of work for adding or replacing some radiators. Are there any rooms that are not getting enough heat?

    It sounds like you have about 52 feet of element total (the part with the fins) and that is well within the capacity of a 3/4" pipe. the boiler is also properly sized to the amount of radiation connected to it. I can see no benefit to the "Home Run" system you are suggesting. The inexpensive 3/4" loop design is why Baseboard was invented. To keep things simple.

    If you want to reinvent the wheel Go for it! 1/2" Pex to each home run will work fine in your design. I'm guessing the building is not being used to park your Boeing 747, so there won't be that much difference in temperature from one room to the next either way you do it.

    Just be sure you leave a place to release or purge the air from the system. Especially the higher 2nd-floor areas

    Let me tell you more about the rooms, and perhaps you can guide me further.

    Dinning Room/Kitchen - 12' run, 18' x 25' (Entry takes up part of the exterior wall where the baseboard would be.)
    Living Room - 12' run, for a 18' x 25' (Backdoor takes up part of the exterior wall where the baseboard would be.)
    (These could be one zone tbh)

    Master Bedroom - 12' Run, 12' x 25'
    2nd and 3rd Bedroom - 8' Run, 8' x 20'
    (Master would be great to be on it's own zone, with the 2nd/3rd can potentially be on one)

    So I could simplify it to 3 zones.

    2nd and 3rd Bedrooms and the Living are certainly colder. The Master and Living do ok with the forced air, however again, those electric bills!

    Other facts:
    This house is located in Brooklyn, NYC, so winters are real. It's a row house, with houses on both sides.
  • omarvelous
    omarvelous Member Posts: 11
    edited December 2020
    SuperTech said:

    Ok, I understand completely now. I'm glad you realized that forced air was a mistake. I suppose its too late to convince you to go with radiant heating. I don't know what you are using for a boiler,  but it is usually a good idea to avoid having too many small zones with their own thermostats. Perhaps panel radiators with thermostatic radiator valves could be used to control the comfort in each room? 

    Radiant heat actually WAS what I wanted to go with. I actually went as far as to buy the manifolds and pex, however at the time it would have added too much height to the floors (this is for the ground floor which is on slab, I had to replace woodflooring, that the previous owner had installed on the slab that rotted due to moisture). I also thought about retrofitting the 2nd floor under the subfloor, but it just seemed a bit much.

    I thought about the panel radiators, and doing a one pipe system. Sizing the rads was one concern. The added cost of the rads themselves with the thermostatic valves, coupled with my understanding of needing to use diverter tees (and finding it rather hard to find them?) was what kind of lead me away from that idea?

    The other idea I thought, was to potentially run mini-splits for hot and cold. I wanted to install them at least for cold, however I figured I could probably just kill two birds with one stone, but I just haven't been to sure about that route.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,388
    How was the heating before you took it apart?
    or
    Did you not have any experience with the house before the heat was disassembled?

    If you have this design, you can be very comfortable.



    Red indicates the baseboard.
    Black indicates 3/4" piping with the direction of flow

    This is one zone with one loop for the entire system.

    if you want to have a separate thermostat upstairs and downstairs then use this configuration.


    This can also be all 3/4" pipe

    if you already have the manifold and want to use it, then you can use 1/2" PEX home run and put motorized valves on each loop. there is a way to open more than one valve with one thermostat. you will need to research that.
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
  • SuperTech
    SuperTech Member Posts: 1,689
    I wouldn't want mini splits as my primary heating system,  especially if a boiler is an option. Honestly I wouldn't want them for cooling either if a ducted system is possible. I've grown to hate the service related problems associated with minis. 
    I would probably stick with 3/4" copper if fin tube baseboards are being used.  But since you have the materials there's nothing wrong with going the homerun route. You definitely have some options with how you proceed. You can do panel radiators without needing diverter tees.  
  • hot_rod
    hot_rod Member Posts: 15,033
    Your best first step is a room by room heat load calc. Any upgrades to the building? If so you may need less emitter, and boiler😀
    Any new system I design I would future proof it and design around a 120- 130 SWT. Low temperature fin tube or some version of panel rads. A home run system with TRVs would be sweet. I’d be surprised if you couldn’t get by with 1/2 runs to the various zones.  The load calc will determine piping size for boiled and manifold runs
    use the free load calculator at www.slantfin.com. Check out their low temperature options. 
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • omarvelous
    omarvelous Member Posts: 11
    SuperTech said:

    I wouldn't want mini splits as my primary heating system,  especially if a boiler is an option. Honestly I wouldn't want them for cooling either if a ducted system is possible. I've grown to hate the service related problems associated with minis. 
    I would probably stick with 3/4" copper if fin tube baseboards are being used.  But since you have the materials there's nothing wrong with going the homerun route. You definitely have some options with how you proceed. You can do panel radiators without needing diverter tees.  

    I assume you are referring to using a bypass valve like this? https://www.supplyhouse.com/Caleffi-301241-1-Pipe-Straight-Thermostatic-Radiator-Valve-for-Panel-Radiators?gclid=Cj0KCQiAw_H-BRD-ARIsALQE_2PLk6Nm_S9D7Ghqas14qzcnUJZ8piLDtGzRQx6M2muUiG2H2KluSAMaAj8zEALw_wcB

    Is there a way to do it with baseboards or radiators like so? https://www.supplyhouse.com/Runtal-UF-2-48-4-ft-UF-2-Baseboard-Radiator

    I honestly would rather avoid panel radiators if I can. I kind of like the low profile from the Runtals, and would deal with baseboards for now.

    I don't have any of the manifolds, pex, or baseboards/radiators as yet.
  • omarvelous
    omarvelous Member Posts: 11
    edited December 2020

    How was the heating before you took it apart?
    or
    Did you not have any experience with the house before the heat was disassembled?

    I'm very familiar with the bones of the house. I'd def consider one loop, I just would like to have some level of control per room. And if I can do one pipe with like TRVs at the baseboards, I'd be happy with that!

    What I'm seeing with TRVs for baseboard is it would be added to the supply side, what I'm not sure about is the return side of the baseboard... I'm told it should be a monoflow/diverter tee to the main line... However I'm not able to find any products that would suffice?

    The ones I do see are always like 1" to 3/4", or 3/4" to 1/2"? https://www.supplyhouse.com/Legend-Valve-302-203-3-4-x-1-2-Bronze-Monoflo-Tee

    Is that what I need? Do I need to run the 1"x3/4" and upsize the 3/4" mains for that or do I run with the 3/4"x1/2" and reduce the return from the 3/4" baseboards?
  • omarvelous
    omarvelous Member Posts: 11
    Ok, I think I see what's possible. I'm reading that I might be able to do the one loop, with TRV at baseboard, I'd just have to install a bypass line, which is a size down from the 3/4", so 1/2", and thus I'd be able to use the 3/4" x 1/2" x 3/4" monoflo tee.

    So let me know if this sounds right:

    From the 3/4" main supply to a 3/4" x 1/2" x 3/4" tee (A)
    From the 1/2" of A tee, run 1/2" copper bypass line to the 3/4" x 1/2" x 3/4" monoflo tee (B)
    From the 3/4" of A tee, install the TRV
    From the TRV install the Baseboard
    From the Baseboard install a Air Vent (if applicable) to 3/4" of B monoflo tee
    From the other 3/4" of B monoflo tee, goes back to the Main

  • hot_rod
    hot_rod Member Posts: 15,033
    Give this journal a read, it shows all the various zoning options, piping schematics, etc.
    https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_19_na.pdf
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • omarvelous
    omarvelous Member Posts: 11
    hot_rod said:

    Give this journal a read, it shows all the various zoning options, piping schematics, etc.
    https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_19_na.pdf

    Thank you! I actually skimmed this before, and it was part of the confusion I had with the need for a diverter tee if I was to add TRV to zone each baseboard.

    In reading the install instructions for the Danfoss TRV's, they recommend using regular tees when creating the bypass line. So I think I'm going to go with what they are calling "series to parallel" piping system: https://assets.danfoss.com/documents/47250/AN000086406172en-US0201.pdf

    I'll run the 3/4" from my main using pex to the baseboard tee, which splits off to the TRV then baseboard and to the 1/2" bypass line with shutoff valve.

    Thanks all for the help!
  • hot_rod
    hot_rod Member Posts: 15,033
    It's always struck me as an odd place to have a temperature control valve, floor level. And also in harm's way when vacuuming :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream