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Copper to pex

Kinda new to hydronic heating, learning more everyday. I'm planning on finishing the girlfriends basement soon and have a few questions. First off it's a new system installed 2 years ago, mix of slant fin and old cast rads, runs 154*F. They made new copper trunk but it's low, would like to replace that with 3/4" PEX, also remove the old rads and go all baseboard. Also add 3 zones not just one. I would like to use 3/4" for each zone as well, looping units off each other and back. Would also like to use circulators for each zone. Here's a couple pics. Unit is a IBC 160K BTU it is a combo unit. Works well just the heat is very uneven and unit is throttled way back cause the old rads I guess?. Any pointers would help.

Comments

  • nordic440
    nordic440 Member Posts: 10
    edited December 2021
    Oh also why does the return tie back into the supply? Seems odd to do it that way?
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,516
    edited December 2021
    before you do anything you need to download the Slant Fin app and do a room X room heat loss of the whole house. otherwise how much baseboard do you need. You need to determine the heat loss first.

    Then baseboards, then pipe sizing and layout, then select pumps etc

    Getting rid of the cast iron may nort be the best idea ....nothing heats better


    The return is hooked in "primary secondary " which is the way those boilers must be piped

    Lokk for information on this in system help on this site

  • nordic440
    nordic440 Member Posts: 10
    Yes I definitely plan on doing that. Gathering information phase right now, lol. They do heat great but are in rough shape and they are all different sizes, some tall and narrow some short and wide. One on the main floor and 4 on the second level! Hence the 3 slant fins they added to the main level, I suspect these are from the 40's and have had a good life for sure. I have installed a forced air system but this is all new to me. I don't really intend on messing with it for a few months, however I would like to atleast run the pex in the walls so I can sheet rock it. Then the baseboards can be installed near the end of the Reno.........
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    You already see how wonderful the other pex looks. 3/4” pex will look worse and expands/contracts a lot more than copper.
    steve
    SuperTech
  • nordic440
    nordic440 Member Posts: 10
    It definitely does. The copper is low for the drop ceiling I wantta install. Pex will be outta sight, not a ton of head room room to start with. Ideally I wouldn't want to modify it but I feel we need the space. Again just tossing around ideas ☺️ 
  • hot_rod
    hot_rod Member Posts: 22,118
    That is not an ideal mix on a one zone system, cast radiators and fin tube. They heat quite differently as you noticed. If they are in different rooms you could zone it so they are separate?

    some of those joists look like oak, or just rough cut fir? It would be a tough drill to get all that piping up in the joist. Maybe you want the new piping tight to the bottom of the joists?

    if you use pex I would insulate it to prevent squeaking where it touches the joists, if you intend to hang below.

    Boiler piping is correct and as per the installation manual. It is a primary secondary piping arrangement.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • JakeCK
    JakeCK Member Posts: 1,356
    nordic440 said:
    Oh also why does the return tie back into the supply? Seems odd to do it that way?
    Ahh the ol' stack of window shakers in the basement. I know them well. Enjoy the virtues of radiant heat. lol

    Also in one of the photos it looks like you have already started finishing the basement or at least insulated the exterior foundation with foam board. Make sure to cover that with drywall or something approved if you back off from this project. Most foamboard cannot be installed and left exposed.
  • nordic440
    nordic440 Member Posts: 10
    I would like to put the pex below the joists. As soon as I figure out what size pex I'm going to be putting up the drywall. Lol gotta love the window shakers eh. I think where doing a mini split system in the future. 
    I can't figure out how to reply to individual posts so lumped it together! Made a crude drawing
  • PC7060
    PC7060 Member Posts: 1,156
    Before you finish the basement I recommend you do moisture testing. Tape a 3’ square of 6-mil poly (seal all edges) onto to floor and walls in few places.  If you see condensing moisture you will need to plan for and manage it (And if you don’t see it. Is you probably will in the spring). 
    You will find this is a real challenge in a house of that age.  

    This guy does a good job summarizing the issues. 

  • nordic440
    nordic440 Member Posts: 10
    Yes we have corrected the moisture issues, there was a small leak from the exterior side. New window wells and grading as well as extending down spouts have fixed the issue. Block cracks where repaired and has been hovering at around 48% humidity for months now. Definitely wouldn't be putting money into it if it wasn't dry ☺️
    I appreciate everyone taking the time to respond! 
    PC7060
  • JakeCK
    JakeCK Member Posts: 1,356
    PC7060 said:
    Before you finish the basement I recommend you do moisture testing. Tape a 3’ square of 6-mil poly (seal all edges) onto to floor and walls in few places.  If you see condensing moisture you will need to plan for and manage it (And if you don’t see it. Is you probably will in the spring). 
    You will find this is a real challenge in a house of that age.  

    This guy does a good job summarizing the issues. 

    That guy spends the whole first 5 minutes of the video talking about how pre 95' houses shouldn't have finished basements. The rest talking about products to use to finish them, and then at the end is trying to sell his own product(A membership). The guy gives me a bad vibe. If I was getting an estimate from him I'd smile and show him the door.

    And his comment about people from the old days not understanding how water works is a load of bull$hit. I'm sure some of the deadmen would have a thing or two to say about that. They were the masters of controlling water right?
    Actually I bet most of these old houses weren't built to have finished basements because they DID understand water. 

    Yes every house older than say 25-30 years wasn't built to have a finished basement. Can they be finished anyways? It depends. But the reality? Even houses that were built to have that space finished suffer from the same issues. Foundation water proofed? Awesome. It'll fail at some point. Vapor barrier under the concrete? Awesome. Lets see what hydrostatic pressure does. Sump pump? I'd prefer a house that doesn't need one! And pumps fail, normally when you need them the most! He talks like all of these things will save your bacon down there. Sorry to bust any bubbles but do you think some plastic under concrete, tar spread on a foundation, and a sump pump is going to save you when the electric is knocked out and the sewers backs up? And most moisture in a basement comes from outside air. How much my dehumidifier runs tracks pretty darn close to what the temperature and humidity is doing outside, not how damp the ground is outside.

    nordic440
  • hot_rod
    hot_rod Member Posts: 22,118
    A series loop like that would work. Keep it under 100' total length and 3/4 should work.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    nordic440
  • yesimon
    yesimon Member Posts: 45
    edited December 2021
    Made a crude drawing.
    Is that series loop one of the 3 zones you're planning (in the basement I'm guessing?). This is your chance to split and balance on a room-by-room basis. Long series loops make for uneven heating unless you have open concept.
  • PC7060
    PC7060 Member Posts: 1,156
    JakeCK said:
    PC7060 said:
    Before you finish the basement I recommend you do moisture testing. Tape a 3’ square of 6-mil poly (seal all edges) onto to floor and walls in few places.  If you see condensing moisture you will need to plan for and manage it (And if you don’t see it. Is you probably will in the spring). 
    You will find this is a real challenge in a house of that age.  

    This guy does a good job summarizing the issues. 

    That guy spends the whole first 5 minutes of the video talking about how pre 95' houses shouldn't have finished basements. The rest talking about products to use to finish them, and then at the end is trying to sell his own product(A membership). The guy gives me a bad vibe. If I was getting an estimate from him I'd smile and show him the door.

    And his comment about people from the old days not understanding how water works is a load of bull$hit. I'm sure some of the deadmen would have a thing or two to say about that. They were the masters of controlling water right?
    Actually I bet most of these old houses weren't built to have finished basements because they DID understand water. 

    Yes every house older than say 25-30 years wasn't built to have a finished basement. Can they be finished anyways? It depends. But the reality? Even houses that were built to have that space finished suffer from the same issues. Foundation water proofed? Awesome. It'll fail at some point. Vapor barrier under the concrete? Awesome. Lets see what hydrostatic pressure does. Sump pump? I'd prefer a house that doesn't need one! And pumps fail, normally when you need them the most! He talks like all of these things will save your bacon down there. Sorry to bust any bubbles but do you think some plastic under concrete, tar spread on a foundation, and a sump pump is going to save you when the electric is knocked out and the sewers backs up? And most moisture in a basement comes from outside air. How much my dehumidifier runs tracks pretty darn close to what the temperature and humidity is doing outside, not how damp the ground is outside.

    Wow, not sure how you got that I was advocating for him and his products. As a FYI, he especially made me cringe when he discuss thin setting tile directly to the subfloor with no decouple layer.   

    The point is he pretty clearly states is the same thing you say above (highlighted).  Majority of pre-WWII basements are not buildable as finished area because it was never the intended purpose for the space. 

    The central point from my original post is the key take away
    Do the 6-mil poly test and if you see condensing moisture you will need to plan for and manage it”

  • Rich_49
    Rich_49 Member Posts: 2,766
    Has anyone mentioned or have you thought about using a manifold and running homeruns of 1/2" to each room / piece of heat ? All emitters will receive same temp and you'll only need 1 gpm to each type also . They were made to use 1 gpm anyway . Might even get to lower temps and increase the efficiency of that boiler a point or two .
    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
    ChrisJ
  • JakeCK
    JakeCK Member Posts: 1,356
    PC7060 said:
    Wow, not sure how you got that I was advocating for him and his products. As a FYI, he especially made me cringe when he discuss thin setting tile directly to the subfloor with no decouple layer.   

    The point is he pretty clearly states is the same thing you say above (highlighted).  Majority of pre-WWII basements are not buildable as finished area because it was never the intended purpose for the space. 

    The central point from my original post is the key take away
    Do the 6-mil poly test and if you see condensing moisture you will need to plan for and manage it”

    Where did I say the majority of pre ww2 houses don't have buildable basements? I said most weren't built for that purpose. Just because it wasn't the intended purpose doesn't mean it won't work. One can drive a screw with a hammer. It'll probably work if you hit it hard & straight enough. lol The highlighted text was an attempt at pointing out that the old timers knew moisture would always be an issue and purposely built them to be utilitarian only. Contrary to what was said in the video. I also disagree that modern houses are any better at keeping the water out. Lets see how dry the basement in an early 00's house with all its water proofing is in another 40-50 years. I bet those foundations will be leaking with the best of em'.

    And I didn't say you were advocating for him. I was just stating I didn't like that what that guy was saying. And why.
  • WMno57
    WMno57 Member Posts: 1,263
    Maybe you already know this, but since you are new to hydronic heat, and asked for pointers.

    Pex for Hydronics needs an oxygen barrier. Most pex sold for domestic water does not have an oxygen barrier.
    I DIY.
    Rich_49pecmsg
  • nordic440
    nordic440 Member Posts: 10
    Rich_49 said:
    Has anyone mentioned or have you thought about using a manifold and running homeruns of 1/2" to each room / piece of heat ? All emitters will receive same temp and you'll only need 1 gpm to each type also . They were made to use 1 gpm anyway . Might even get to lower temps and increase the efficiency of that boiler a point or two .
    I have thought about that....... definitely easier to run 1/2 as well 


    Rich_49
  • nordic440
    nordic440 Member Posts: 10
    WMno57 said:
    Maybe you already know this, but since you are new to hydronic heat, and asked for pointers. Pex for Hydronics needs an oxygen barrier. Most pex sold for domestic water does not have an oxygen barrier.
    Yepperz was one of the first things I researched!
  • mattmia2
    mattmia2 Member Posts: 9,625
    Many of the larger houses in detroit built in the 20's have beautiful finished basements.
    JakeCK
  • nordic440
    nordic440 Member Posts: 10
    yesimon said:
    Made a crude drawing.
    Is that series loop one of the 3 zones you're planning (in the basement I'm guessing?). This is your chance to split and balance on a room-by-room basis. Long series loops make for uneven heating unless you have open concept.
    Yes the basement will be a zone, then main floor followed by second floor. I will have walls open on the main and upper levels once basement is done so running new lines will not be an issue. Just need to get this basement sized and the lines ran and get this foam covered up! Basement is not huge 24'X24' 
  • nordic440
    nordic440 Member Posts: 10
    Well this was the final result. Works amazing. 1/2 OXY PEX to each baseboard. Very even and I think the boiler is more efficient. The knowledge I gained from this site was great. 
    mackneerd
  • Jamie Hall
    Jamie Hall Member Posts: 23,275
    Ah yes. Basements. Just for laughs, may I point out that all two of the three houses which I maintain have unfinished basements. In both, the basements are used, quite successfully, for a variety of projects -- not just utilities, but food storage, carpentry workshops, etc. The bigger, in Cedric's home, dates to 1780 or thereabouts. It is not waterproof, nor was it ever intended to be. It has, in fact, neat gutters running around the perimeter to accept the inevitable water which comes in and take it neatly away to daylight. Works a treat. The basement is never damp -- higher humidity, yes (usually around 70%) and not heated by anything except Cedric and the surrounding ground, but very pleasant.

    The other was carefully worked on to be finishable (it isn't, but that's another story). Careful waterproofing (right...) and, of necessity, two sump pumps. It isn't quite as old -- 1820, we think -- and would have been better had no waterproofing been attempted.

    If you don't want water in your basement, however, don't try to keep it out with waterproofing. That will fail. Rather you need to work outside, to make sure groundwater does not and cannot come up to the foundation. That means drains at footing level, with fabric and gravel and the lot, open to daylight somewhere. Done well, that will be a good long term solution. Anything else -- particularly applied on the inside -- is doomed.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Larry Weingarten