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are we over zoning???

So basically your boiler will not fire unless zone 1 is calling? If your reset curve (asuming you have a odr) is calibrated closly to your loads then zone 1 will be very near constant circulation. If it's not and zone one has long on /off cycles r,there will be times when your other zones may be starved,especially given the low mass of your boiler, this may effect comfort- on the plus side low comfort =saved energy.

For houses that are fully occupied I think single zone flow balanced systems make sense. All those thermostats and circulators may be easier for an installer than carefully balanced distribution, but if the occupants don't really utilizes this zoning, and just keep the whole house at 68, then what's the point. A single zone at close to constant circ. will derive the highest efficiency from your condensing boiler. Tekmar Tn4 is about having the advantages of wide zoning with less of the pitfalls.

Honywell is making a very tn4 like system (AQ2000) , it has a strong retro fit advantage: the room temperatures units work with 2 wires, Tekmar requires 4.


  • Rich Swatton
    Rich Swatton Member Posts: 4
    Are we overzoning?

    Are we over zoning?

    My house has four zones.Zone #1 First floor zone, 2 bedrooms, bathroom, living room, and kitchen.Zone #2 Family room.Zone #3 OfficeZone #4 Bathroom (radiant).I have a Munchkin boiler with outdoor reset and domestic HW priority.All zones are baseboard except the lower bathroom which is radiant.I down loaded the boiler operating history for the year and found the heating call cycles extremely high.
    I came up with a simple solution.I took the zone with the largest demand (Zone #1) and connected the thermostat to the boiler TT disconnecting the taco relay end switch. The other zones are still connected to the Taco multi Zone Relay witch only actuate the circulators and not the boiler.I think I will definitely save on gas consumption.

    My next step will be to replace the circulators with zone valves with a variable speed pump.I will operate the boiler again with Zone #1, saving on electricity.
  • gerry gill
    gerry gill Member Posts: 3,078
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • Hvacman
    Hvacman Member Posts: 159
    Is there?

    Is there such a thing as overzoning? I have a zone each in my 3 bedrooms, kitchen, living, dining, 2 baths, back hall, and basement. I reset agressively at the stats and boiler. The only zones that can't call on the boiler are the baths. I don't have short cycling issues... There is no substitute for a mod-con with a great turn down ratio.

  • Love it!

    If that's not feasible though, a buffer tank is another decent choice as well.
  • jp_2
    jp_2 Member Posts: 1,935
    yes and no

    if you tend to have several small zones open at once you're OK, if little zoning are going on/off/on/off the boiler will do the same, like driving fast/slow/fast/slow

  • just because you keep rooms at the same temperature doesn't mean you aren't utilizing zoning. zoning may be required to keep different areas at the same temperature instead of different temperatures as they may tend to on their own.

    balanced distribution is nice (and more powerful than I once thought), but it has a lot of limitations and imperfections.

  • With a good room by room heat loss, and parallel piped panel rads the importance of accurate flow balancing is not so great, add trv's and it's automatic.

    Many installers over-pump and zone so freely because a truly flow balanced output is hard to achieve, as carefully planed as it may be. In all likelihood lots of trial and error corrections may be required. Zone valves and smart controls make sense for the high end installer. For those who do not seek absolute control a single zone flow balanced system is in my opinion a viable option, even with the headaches establishing that balance may require.

  • ah, gotcha. when you said "balanced distribution" I assumed you meant the set and forget method, not TRVs. You are right, of course. with automatic TRVs, the game is different.

    Still there are limitations, primarily in things like automation and variability of response, making it not suitable for all projects. But as long as the emitter can respond to the space it's in, you are ahead of the game, absolutely.
  • Rich L.
    Rich L. Member Posts: 414
    Buffer tank

    That's where a buffer tank would come into play JP. If you have micro zones and lots of on off it will really save on the boiler cycles. A mod-con boiler only turns down so far....
This discussion has been closed.