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Single zone boiler plumbing

cfar
cfar Member Posts: 5
First time poster,  long time lurker.

I'm installing an I series Rinnai combi boiler and have a few questions.

My first question is feed line to the boiler half of the system. Rinnai has a diagram in there install manual that I'm using as a basis for the layout of my system. I'm curious if the teal markings (DCW) are plumbed correctly. Simply a tee fitting from the DCW to the supply line for the boiler. I have been looking at several pictures and they all differ some. Next is the location of the single pump being located after the air separator.  Not really a question as it's more of a verification.


Missing from the diagram is the condensate line with a neutralizer.


Any questions and concerns are welcome.

I'm sure Ill have many more questions once the boiler arrives and install begins.

Comments

  • cfar
    cfar Member Posts: 5
    Next question.

    Can I still use the water heater portion of the combi boiler while I plumb the boiler system if I close the system after the expansion tank?
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 3,357
    edited September 11
    OK, the teal line is correct. Just install a ball valve on the branch to the DCW inlet. 

    The boiler needs to be filled with both the heating water and domestic water in order to work properly. With all air pockets removed. 
    Often wrong, never in doubt.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,362
    where is your circulator for the main loop? it should be located a the red mark where it says "system supply"
  • cfar
    cfar Member Posts: 5
    where is your circulator for the main loop? it should be located a the red mark where it says "system supply"

    My mistake. Red is circulation pump.
  • cfar
    cfar Member Posts: 5
    OK, the teal line is correct. Just install a ball valve on the branch to the DCW inlet. 

    The boiler needs to be filled with both the heating water and domestic water in order to work properly. With all air pockets removed. 

    Ok. So if I understand correctly, I CAN NOT use the water heater portion of the unit while I take my time to plumb in the boiler's supply and return lines?


    Thank you two for your help.
  • I would wait until you have your heating piping up and running, purged of all air. When there is a call for DHW, the internal pump in the Rinnai boiler will pump water to and from the heat exchanger to heat the DHW. If the boiler is not properly filled or not free of all air, it could fry the pump.
    Often wrong, never in doubt.
  • hot_rod
    hot_rod Member Posts: 16,878
    edited September 12
    If it is a combi there is a circ inside the boiler
    In the piping schematic you show, a valve on either end of that straight horizontal pipe, and you could fill and run the boiler.

    On the left side put a pump iso valve/ flange, where the red blot is on the pic. On the right side a webstone purge ball valve. Now you have two useful valves and could pressurize and run the boiler.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    GGross
  • cfar
    cfar Member Posts: 5
    Thanks for the info. I'll do just that!

    Is there anywhere else you think I should place more valves, unions, etc.? 

    I will be uploading my build process once I start making some real progress which should be this weekend.
  • hot_rod
    hot_rod Member Posts: 16,878
    I'm not a huge fan of unions that will never get used. The circ by default are unions, that is the most common replacement item.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream