The Wall
Forum / Radiant Heating / manifolds in series?
  • Post a Reply to this Thread

    manifolds in series? (11 Posts)

  • jonny88 jonny88 @ 8:53 AM
    Contact this user

    manifolds in series?

    I came from a call today.A combi boiler in a 1200 sqft apt.Domestic water goes through an electric water heater then to fixtures.(customer complained of nhigh electric bills).On the heat side there is two six loop manifolds piped in series all with actuators.Radiant piping is minitube.Has anyone ever had success piping two manifolds like this,by the way there is problems with heat in every room.Thanks
  • Mark Eatherton Mark Eatherton @ 9:57 AM
    Contact this user

    Clarification please...

    So the fluid leaves the boiler and goes into the first supply manifold, and then out of the return manifold, and into the second supply manifold, then out of the second return manifold and into the third supply manifold, and so on and so forth?

    Or does the supply leave the boiler, go into and through the first manifold, then on to the second supply manifold, through it to the third supply manifold and so on.

    If its the latter, they are in parallel, not series,

    If they are as in the former, then they are wrong, and I am amazed you are even able to get any flow through the circuits…

    Got pictures?

    ME
    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.
  • jonny88 jonny88 @ 9:42 AM
    Contact this user

    parallel

    Hi Mark and thanks for your time.NTI 200 combi backed up with 38 gallon electric Rheem water heater.
    Heating side.11/4 primary loop.Closely spaced tee 11/4x1
    Supply goes through Viega enhanced mixing station.Viega spceked a 12 loop manifold.Plumber put in two six loop manifold.I guess I am wrong and piped parallel.I got my terminology wrong.ON the mixing station when I opened the purge screw on pump I got no water.Nti rep says system is airbound.He didnt like the piping arrangement but thinks it will work.By the way the apt is 1200 sqft.heatloss is 25k.Boiler mminimum firing rate is 55k.
    NTI said its a good boiler but wrong application.So 2 yrs later tennents are still cold.Even if it is airbound do you think I should build a header and split manifolds.
    Domestic side I am going to redo as to manufactutres specs.
    I apreciate your help ,John
  • Mark Eatherton Mark Eatherton @ 10:05 AM
    Contact this user

    Locked up 3 way?

    I took a gander at the Viega mixing package. That is essentially a 3 way valve. If it is not cold purged, it is not purged. Once purged, it should work normally.

    Get some pictures if you can. They're worth a million words :-)

    A simple schematic would help too. Having two manifolds in parallel is not a big deal so long as they are correctly piped.

    Pressure wise, you need 1/2 PSI per system vertical foot height above the boiler, plus 5 PSI. Minimum setting is typically 12 PSI if the appliance is on the top floor.

    Is the radiant pump working? A hot pump doesn't necessarily mean its "working". In fact the hotter the pump casing, the less water is moving (water cooled circulator). Amperage test are useless because with this type of motor, it draws the same power under normal circumstances as it does with a locked rotor. If there is a ball valve in the circuit with the pump, you can close it quickly and listen for a HISSssss, indicating flow. If it is silent, you have no flow, and it may not be the pumps fault. Could be air bound, especially is someone tried to fill and purge with hot water.

    Are you sure the 38 gallon tank isn't being used as a buffer tank to keep the boiler from short cycling? It's not real common to use electricity to back up a gas fired appliance. BIG difference in operating costs...

    Keep on it. You'll figure it out.

    ME
    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.
  • jonny88 jonny88 @ 7:13 AM
    Contact this user

    buffer tank?

    Definitly electric water heater,I know it sounds hard to believe.we want to put in a buffer tank to prevent short cycling but the boiler room is so tight there is no room.we are going to disconnect electric and make it into a storage tank wit circ,aquastat and flow switch.
    This system has been over complicated as some reps got in there and sold a lot of equipment which made an easy install into a mess.Original plumber walked out on job.By the way this is one of five manhattan apartments all experiencing the same problem.Mark,would you ever put in a 12 port manifold?In my eye it just seems so hard to balance and get flow through all loops.I will take pics when I go back in a few days.Again thanks for your help as always,John.
  • Mark Eatherton Mark Eatherton @ 6:15 PM
    Contact this user

    Is this an open system?

    Make a whole lot of difference...

    I see you are in NYC, and open systems are not approved there. Get us some good pictures and we'll see what we can see.

    ME
    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.
  • jonny88 jonny88 @ 11:05 AM
    Contact this user

    HI Mark,

    so we went back to the scene of the crime.Condo board want us to start on duplex apt.We got the design layout from viega which helped in locating hidden manifold.so every balancing valve is filled with a rust color and does not work.Heating side of boiler one set of closely spaced tees (8inchs apart.)These support four manifolds covering 3200 sqft.In the cellar on a six loop manifold,3 loops have viega pipe other 3 had a blue color pipe which we discovered was not o2 barrier.we figure the non oxy barrier pipe is causing system to rust,there is a lot of ferrous material on near boiler piping.We want to eliminate infloor heat in cellar and run radiant on walls.(very expensive Tile floor).we want to avoid ripping it up to run proper pipe.Im babbling.Next week we go back,I will take pics ,again thanks for your interest and help.
  • jonny88 jonny88 @ 11:07 AM
    Contact this user

    HI Mark,

    so we went back to the scene of the crime.Condo board want us to start on duplex apt.We got the design layout from viega which helped in locating hidden manifold.so every balancing valve is filled with a rust color and does not work.Heating side of boiler one set of closely spaced tees (8inchs apart.)These support four manifolds covering 3200 sqft.In the cellar on a six loop manifold,3 loops have viega pipe other 3 had a blue color pipe which we discovered was not o2 barrier.we figure the non oxy barrier pipe is causing system to rust,there is a lot of ferrous material on near boiler piping.We want to eliminate infloor heat in cellar and run radiant on walls.(very expensive Tile floor).we want to avoid ripping it up to run proper pipe.Im babbling.Next week we go back,I will take pics ,again thanks for your interest and help.By the way it is not an open system and all manifolds are piped in parralel if I understand corectly,
  • Gordy Gordy @ 11:14 AM
    Contact this user

    Non barrier loops

    Any way to separate the 3 non barrier loops, and run off a flat plate heat exchanger, and separate manifold? Be nice to keep the I floor in the cellar.
  • jonny88 jonny88 @ 7:23 AM
    Contact this user

    heat exchanger

    I actually had a friend suggest that to me.I am certainly going to bring it up .Again there is three remote manifolds.I think a total of 27 actuators.Every balancing valve is clogged with a rest color.Is it possible the non barrier pipe is responsible for this.I am going back tomorrow and will take pics.I really apreciate your responses.
  • RobG RobG @ 2:07 PM
    Contact this user

    To better serve

       To better serve the customer, I would try flushing the system and re-piping it using a flat plate heat exchanger and non-ferrous components for all of it, not just the remote manifold. After all, the heat comes from the boiler not from the remote manifold with the non O2 tubing. I have non O2 barrier PB systems that have been working for over thirty years.
        With a heat loss of 25K BTU there is no reason for an electric back-up but you definitely need a buffer tank with a boiler of that size. You can reuse the the water heater as a buffer tank or put in a real buffer tank that will fit. I understand space is an issue but there is probably a buffer tank that will fit your application.

    Sorry, I missed that it was a combi. Use the combi as as designed, and use the electric as a buffer, or install a real buffer

       I'm watching the Daytona 500 and trying to use the computer at the same time. I have a hard time walking and chewing gum as well :) 

       As Mark said, post some pics.

    JMHO,
    Rob
    This post was edited by an admin on February 23, 2014 3:18 PM.
  •  
Post a Reply to this Thread