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Best way to add a zone to a mono flow system

Markmc22 Member Posts: 3
What’s the most efficient way to add a zone to a mono flow system


  • Zman
    Zman Member Posts: 7,573
    With old existing systems, it is usually easier to tie in at the boiler room. More details would be needed. Flow requirements of the new zone as well as some as built sketches and/or pictures.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Markmc22
    Markmc22 Member Posts: 3
    The plan is to make a piece of baseboard that was recently added to a sun room it’s own zone. The rest of the house is a one zone mono flow system. Can I just tee into the supply add a zone valve and tie the return in?
  • GW
    GW Member Posts: 4,701
    Mark not really, but you could. If you do that your main zone will need to be on in order for your new zone to get any heat. I would think your new zone will need more run time than your main house zone
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
  • Markmc22
    Markmc22 Member Posts: 3
    So how would you recommend doing it
    HVACNUT Member Posts: 5,863
    Just like @Zman said. Make it its own isolated loop with its own circulator, switching relay and thermostat.
    EBEBRATT-Ed Member Posts: 15,616
    @Markmc22 The above is good advise. Put enough baseboard in the sun room to do the job. You should do a rough heat loss to make sure you have enough. If you run 3/4 copper supply and return will give you 40,000btu. You could also use pex. You need a thermostat, switching relay and a circulator. You can run 1/2" and get 15000 btus

    The sun room will probably have more heat loss than the house on average. If you just tie into the monoflow zone you probably won't be happy.

    The other issue is is their a chance of the sunroom baseboard and piping freezing in the winter? If so and the heat loss is small you might want to consider some electric baseboard