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Wood with mod/con. Piping help please

Chrissalva Member Posts: 1
Hey guys,

I'm putting in a Harman SF260 with a mod/com backup. The system is mostly cast iron radiators with thermostatic heads on them. I also have an indirect DHW tank. What do all recommend for a piping method? Primary/secondary? The manual doesn't show a tie-in with a mod/con. Is there any diagrams out there? I was also told I should put a mixing valve in to prevent the water temp getting too high and short cycling the thermostatic heads. Any thoughts/experience with that? Any help would be awesome. Thank you.



  • Zman
    Zman Member Posts: 7,569

    Here is a good read on the subject.


    The points I would be most aware of is the need for a buffer tank and if the boiler is going to be in the house, a good thermal bypass loop.

    You cannot just shut off a wood boiler the potential for overheating is huge.

    The expansion tank location in the manual is incorrect.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein