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Primary , secondary loop design

Sgtdng
Sgtdng Member Posts: 19
After fighting with my current boiler company for several years they finally are sending me a new unit. This new unit comes with a manifold for the primary and secondary loop. The manifold is 1.5 inch , but I have 1 inch on my secondary. They did say I can reduce from the manifold.  I want to redesign this entire setup so this new boiler will be at its best and most efficient. 
The current setup was a copy of what I seen on a display at menards and exactly what my in-law is using in his garage(which has worked with out failure for years) but with a different boiler. Wondering if someone may be able to give me a better design for this new boiler?
I have talked to the boiler company and they just send me vague printouts that don’t tell me much. 
The boiler has an internal pump, and I have an external pump for the secondary, both controlled by the computer in the boiler .  I am using this for just infloor heating tho it is a combi boiler. It is heating 6 loops but all loops are heated at the same time since the heating space is one big open space. I will try to post a picture of what I have now.  The boiler will need to stay in the same location, but I can change everything else other than the manifold for the 6 loops. Any help would be greatly appreciated.

Comments

  • hot_rod
    hot_rod Member Posts: 22,107
    You already have a primary secondary piping with the Webstone tee, why change to a header below the boiler. Certainly you cannot use both.

    What size is the boiler? if anything the boiler piping may be a bit small to the P/S tee assembly. If that is 3/4"?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    GGross
  • yellowdog
    yellowdog Member Posts: 157
    Cut the pipes off at the webstone tee and pipe it per the new boiler manufacturers single zone piping diagram. Why put in a combi when you are only using space heating? The 1.5 piping on the boiler primary loop seems big to me. Are they putting in the proper sized boiler for your heat loss? If its a combi, its probably very oversized for your heat load.
  • GGross
    GGross Member Posts: 1,040
    Ah Kiturami my old nemesis... It's a tankless water heater heat exchanger, not a fan.

    What is the current problem with the system? You are piped primary/secondary right now
  • Sgtdng
    Sgtdng Member Posts: 19
    It’s a noritz combi boiler currently and noritz finally decided to ship me a new boiler since the heat exchanger blew all to hell. The current piping on the primary is 3/4 and the secondary is 1 inch.  Noritz was trying to tell me a couple years ago that the piping was all wrong causing the combustion issue that I was having at the time .  I wanted them to send me just a heating boiler, but they said they don’t have one just for heating and said they had to send me another combi boiler. The reason I originally bought a combi was so I could add domestic water to the shop.  I have not been able to get domestic water from the house, down to the shop. So I am only using it for heat till I can possibly get a shallow point well done.  
    I believe the pump should go closer to the zone manifold, but the expansion tank should still be at the highest point. ( noritz wants it lower) with the exception of the valves, expansion tank, safety valve, and pump, what else really needs to be in this loop?  
    Here is a screen shot of the manifold they are sending me, a shot of the generic design they sent. 


  • Tom_133
    Tom_133 Member Posts: 884
    sgtdng,

    I am noticing a few things that are kind of not ideal.
    1 according to the pic you show from the manufacturer your expansion is not in the ideal spot, they and most put it on the secondary side.
    2 it appears you have your circ on the secondary pushing toward the closely space tees?

    That may be leading to some issues.

    Tom
    Tom
    Montpelier Vt
  • GroundUp
    GroundUp Member Posts: 1,905
    Just don't use the header. Pipe it to your existing primary lines direct from the boiler connections. All done.
  • GGross
    GGross Member Posts: 1,040
    What is the minimum firing rate of this unit?
  • hot_rod
    hot_rod Member Posts: 22,107
    Sgtdng said:
    It’s a noritz combi boiler currently and noritz finally decided to ship me a new boiler since the heat exchanger blew all to hell. The current piping on the primary is 3/4 and the secondary is 1 inch.  Noritz was trying to tell me a couple years ago that the piping was all wrong causing the combustion issue that I was having at the time .  I wanted them to send me just a heating boiler, but they said they don’t have one just for heating and said they had to send me another combi boiler. The reason I originally bought a combi was so I could add domestic water to the shop.  I have not been able to get domestic water from the house, down to the shop. So I am only using it for heat till I can possibly get a shallow point well done.  
    I believe the pump should go closer to the zone manifold, but the expansion tank should still be at the highest point. ( noritz wants it lower) with the exception of the valves, expansion tank, safety valve, and pump, what else really needs to be in this loop?  
    Here is a screen shot of the manifold they are sending me, a shot of the generic design they sent. 


    The primary loop is the loop that has the expansion tank in it. Sometimes it is the boiler loop, sometimes the system loop
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    GGrossRPK
  • GGross
    GGross Member Posts: 1,040
    that was driving me nuts as well lol. Noritz drawing will work but I'm 90% certain that whoever sent that does not know why. I'm still thinking we need to know what the actual input rates are for the unit
  • Sgtdng
    Sgtdng Member Posts: 19
    GGross said:
    What is the minimum firing rate of this unit?
    the best I seen in the manual they sent is the heating side say 18000 min and 100000 max btu/hr 

  • Sgtdng
    Sgtdng Member Posts: 19
    GroundUp said:
    Just don't use the header. Pipe it to your existing primary lines direct from the boiler connections. All done.
    According to them they want the primary to be minimum of 1 inch and secondary to be 1 pipe size bigger than the primary.  My secondary is currently 1 inch.
  • Sgtdng
    Sgtdng Member Posts: 19
    Should the expansion tank be on the primary or secondary loop. ?Currently it is on the primary at the highest point of the plumbing since it’s connected to the air trap or air eliminator. 
  • GGross
    GGross Member Posts: 1,040
    edited February 22
    Sgtdng said:

    Should the expansion tank be on the primary or secondary loop. ?Currently it is on the primary at the highest point of the plumbing since it’s connected to the air trap or air eliminator. 

    Whichever loop has the expansion tank installed is referred to as the primary loop. So an expansion is always installed on the primary loop. It actually doesn't matter which loop its installed in really, but it should be on the suction side of the circulator or circulators of the loop it is on for best practices, currently it is installed on the flow side not ideal
    Tom_133
  • hot_rod
    hot_rod Member Posts: 22,107
    it's really more about flow rates of you exact system for pipe sizing. That section between the tees can, will see two directional flow depending on flow rates in the boiler loop and secondary loop.

    No harm in having a larger sized header. If it is too small to handle the total flow then the boiler may run up to high limit quickly and go into lock out.

    Here is a good read for those looking to better understand primary secondary piping.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    GGross
  • Sgtdng
    Sgtdng Member Posts: 19
    GGross said:
    Should the expansion tank be on the primary or secondary loop. ?Currently it is on the primary at the highest point of the plumbing since it’s connected to the air trap or air eliminator. 
    Whichever loop has the expansion tank installed is referred to as the primary loop. So an expansion is always installed on the primary loop. It actually doesn't matter which loop its installed in really, but it should be on the suction side of the circulator or circulators of the loop it is on for best practices, currently it is installed on the flow side not ideal
    Ok, so does the expansion tank need to be installed with the air extractor?  If I create a bigger secondary loop I can install that before the pump on the secondary, and I can run my primary loop from the boiler and connect that to the vertical pipe that would now be part of my secondary. I always thought the primary loop was the loop from the boiler. And secondary was that went into the floor. 
  • GGross
    GGross Member Posts: 1,040
    In my opinion your tank would be better located on the return of the boiler loop. It doesn't need to be installed on the air purger, and the air purger is currently located in a decent place for its purpose. I wouldn't switch the tank to the other loop personally.
    hot_rod