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    Best thermostats for 10 zone system (3 Posts)

  • 1970ConcreteWonder 1970ConcreteWonder @ 12:01 PM
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    Best thermostats for 10 zone system

    We replaced a way oversized oi fired boiler with indirect HW (last year oil bill $5500) with a gas fired Triangle Tube Solo. I won't go into the absolute nightmare that was the installation (hint, the Taco Bumblebee circulator was installed upside down - digital display unreadable - and the installer argued that it was perfect). Anyway, as part of the quote, he included a Honeywell ProSeries thermostat "smart" system. We were unable to view the "system" before installation because he kept putting us off and telling us nothing had arrived etc. He never asked about our lifestyle to find out that we work from home on day a week. After he finished, we discovered that he put in FocusPro 6000 which was basically what we had. I called him to ask about the "system" as I had researched a system that was interconnected and how they are "smart". The original builder had designed the home to maximum efficiency for the time (1968-1970) and had put in 10 zones (literally one per room including the bathrooms). We were looking for a system that would talk to each other and stagger the on times etc. We had mentioned the redlink system and the installer said these are "better". As for the smart part, he said they are adaptive and learn how long it takes to heat the house. We had installed top of the line DIY programmable thermostats when we moved in 3 years ago and these were also adaptive.
    We are removing the ones the installer put in because he is charging us an outrageous amount of money for them. We will re-install the DIY ones we had but would like to get more control for parts of the house. I work from home one day a week and would like to program that day in (for at least the part of the house I use). Our old thermostats were 5-2 and the FocusPro 6000 are 5-2 as well. We need 7 day for 2 rooms. We have a cast iron Baseray baseboard hydronic system. We have a new installer who is going to fix the serious errors from the other installer and get the outdoor reset going (other installer turned it off).

    I would like to get a WiFi system for 2-3 rooms in the house because one of use sometimes comes home at odd times during the day and our heat system takes time to get to target temperature. I am interested in the Nest but want to hear what everyone thinks is best.

    I have LOTS more info if you need.
  • Zman Zman @ 8:25 AM
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    Well...

    Your boiler will run at peak efficiency if you set up the outdoor reset. The most efficient outdoor reset curve will use the coldest water temp possible. Colder water makes heat system respond to changes in thermostat settings very slowly.

    Outdoor reset and thermostats that are constantly changing the room temps do not work well together. The reaction time is too slow for to recover from a temp setback.

    Over zoning houses tend to make the boiler short cycle. This decreases overall efficiency. 10 zones are not more efficient.

    I think you have two choices:

    Install 10 very fancy t-stats and leave the the boiler set at a fixed high (inefficient) Temperature. This will give you the feeling that you are saving money, in reality you wont.

    Install 10 or less (grouping zones together) simple non programmable t-stats and set the boiler at the lowest possible temps via outdoor reset. Do not change the settings. just set it where it is comfortable.This approach is very boring, but you will be more comfortable and will save more money.

    If you decide to spend a bunch of money fussing with the indoor temperatures, look into a product with indoor feed back like the tekmar whole house controller. It will do what you want with the indoor temps and still keep some efficiency of the modulating boiler.

    Keep in mind that every time you change the indoor temp, you are not just heating the air. You are raising the temp of the entire mass of the house. It takes significant energy to do this.

    Carl
  • djohn djohn @ 10:48 AM
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    too many zones

    10 zones seems ridiculous for any house unless you are talking MJ23 mansion.

    1 zone per level is a good, energy saving idea. If you want it fancy, maybe separate zone for bedrooms - but are they insulated? (walls, ceiling, floors)

    Ecobee is the solution for wifi smart thermostat and I will be using it for my 3 zone system with 1 stage hydronic, 2 stages forced air heat and 1 stage cooling. Awesome product.
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