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Upgrade to old system

So I have a friend who just purchased a home with an interesting heating setup. The original part of the home was once heated with steam and cast iron radiators. The two additions added on to the rear are baseboard radiant heat. The entire house was converted to hot water when the additions were added, but the steam piping and radiators are still in use now with hot water. So currently the home is heated with an older cast iron natural gas fired Utica Boiler. The boiler utilizes one Taco single speed circulator on the return side of the boiler and a horizontally mounted expansion tank also. The heat is controlled by a single thermostat upstairs on the main floor. The problem is, the front part of the home is usually warm but the rear is always cold. I was thinking about splitting the home into three separate zones with one single new ECM Delta T circulator (prob new Taco Bumble Bee) relocated to the supply outlet, along with a new vertically mounted expansion tank and Spirovent. Also three zone valves with three thermostats. Was also thinking about an outdoor reset control. I would like to get some thoughts on this idea, and also any thing that maybe should be added. Not looking for suggestions to use a Delta P pump though, and the boiler is not going to be changed for now, so please no suggestions for that. I would love to hear what the experts here have to say.


  • SWEI
    SWEI Member Posts: 7,356
    Room-by-room heat loss

    and radiation survey?
  • Prospect_Handy_Man
    Prospect_Handy_Man Member Posts: 32
    thanks for reply

    Rear part of home is farthest away from the boiler, and therefore the longest loop. So the thermostat in the front part of the home is satisfied before the rear gets warm. Which is why zoning will be essential. Moving the thermostat will just overheat the front of the home, and trv's will be too expensive too add to all the cast radiation. The baseboard is sized correctly.
  • SWEI
    SWEI Member Posts: 7,356
    Sized correctly

    by what standards?  Do you have a room-by-room heat loss?
  • Prospect_Handy_Man
    Prospect_Handy_Man Member Posts: 32
    Good Thought?

    I'll have to do the calculations myself to be sure. I wrote that because they were professionally installed. But then I got thinking, if they were very "Professional" than I wouldn't have anything to fix when it comes to comfort. How should I calculate the size correctly? I'm no heating expert, but with help from some fine people on this site I have maximized the efficiency and comfort of a commercial steam system that was not working well at all in a large commercial building I work in. This is a field I am working on pursuing as a career, and I love to learn more. I read about heating systems all the time, and how they work. I have certainly found a passion in it.
  • SWEI
    SWEI Member Posts: 7,356

    the heat loss calculation tells us how many BTUs each room should need on a design day in order to maintain a specific indoor temperature.  The radiation survey tells us how many BTUs each emitter will put out at a specified water temperature.  Between the two of them, we can determine whether the system is balanced (I'm guessing not) and if so, the temperature of water which will allow the system will heat all the rooms at design conditions.  Balancing radiation will improve both comfort and efficiency.  It's absolutely worth your time, and something that will set you apart from the pack should you decide to pursue this as a profession.

    http://www.caleffi.us/en_US/caleffi/Details/Magazines/pdf/idronics_12_us.pdf is a really good starting point if you want to understand hydronic heating.  The rest of that series constitutes a graduate course of sorts if you are inclined.
  • Dave H_2
    Dave H_2 Member Posts: 503
    Splitting to three zones,

    Just splitting up the zones and the radiation part will help with the comfort levels in the home. You've got different types of radiation and they respond differently as you can tell.

    The front satisfies quickly therefor starving the back of the house for heat. Separating the zones with zone valves will let each area run until comfortable. However, doing the math with ensure that the size of the zone valves are accurate and the BumbleBee will provide the correct gpm at maximum demand. If it does not fit the demand of the system, you can still look at a 00VDT to get the same results.

    Adding outdoor reset will also help with the economy of operation but will not adjust the heat delivery to the room. Meaning, if all you do is add reset and change nothing else, you will experience the same situation as you have now.

    Dave H.
    Dave H