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Looking for combi unit - radiant and dhw

Looking for wall mounted combi boiler with dhw. Must have non ferrous heat circuit since pex is non barrier. Heat load is 30k, need 2 gpm dhw. This is for a 6 unit apt. building, so will need 6 possibly.




  • kcopp
    kcopp Member Posts: 4,395
    There are lots of.....

    combi units.  The non barrier tubing will be hard to just hook up to w/o a heat exchanger. There are some ferrous components in the boilers. The circulator primarily. You could swap out the circulators and then embark on a YEARLY cleaning of the water side and add a dose of oxygen inhibitors.....

    I have used Smith GC160/ Embassy Onex, Bosch Greenstar, Triangle tube Excellence and Embassy Axia. Triangle Tube also makes a Challenger boiler but the hot water output is not great.
  • Matt_Connolly
    Matt_Connolly Member Posts: 14
    I used to sell Monitor Boilers

    And they had a combi unit, but they don't sell in the US any more. I thought there were some asian units out there that were cheap - they were one of the reasons Monitor stopped selling. I don't want to go crazy on the controls and hx / pumps. Seems like you could take a good wall mount condensing unit and put a dhw hx with a flow switch trigger when water flows thru the dhw hx. Thoughts?
  • kcopp
    kcopp Member Posts: 4,395
    edited November 2013
    depending on....

    your hot water needs the TT Challenger might work. It has the one block and two separate coils of copper pressed into the block... no flow switch to break and the waters are kept totally separate. Moreover the water in the system never touches the Alum block.

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