How to split one heating zone to multiple heating zones?

Discussion in 'HVAC Heating & Cooling' started by lmei007, Sep 21, 2007.

  1. lmei007

    lmei007 New Member

    Messages:
    154
    Location:
    Maryland
    Hi Everybody,

    Winter is now coming. This year will be the first year for us to pay heating bill becaues we just owned a house. We are neverous. A 1600ft, basement is not included, ranch only has one zone (oil, hot water, in MA) and some heated rooms (in basement) we are not going to use them right now. We are thinking about split it into at least four zones.

    Please give me some advices. You can find photos about my heating system. I created two diagrams: one is for existing system and one is my draft new plan. They are all here: http://www.flickr.com/photos/lmei007

    Do you think one pump for all new loops is ok or not?

    How about use Taco Heat Moto Zone Valves or Electronic Ball Valve (EBV) Zone Valve, Taco SR506 Switching Relay, Taco ZVC406 Zone Valve Control and thermostats from Taco or Honeywell? Please give me you recommendation.

    How about wireless thermostats?

    thanks,
  2. Furd

    Furd Engineer

    Messages:
    446
    Location:
    Wet side of Washington State
    It is not clear from your drawing so the first thing I will ask is if you have separate supply and return piping?

    From the photographs it appears that you may have Monoflo tees in a one-pipe system.

    While it can be done, four zones in that small a house is likely not practical. The economic return for the capital costs involved will take decades to recover.

    I do not like heat-actuated zone valves. They are prone to failure in my opinion. I do not know anything about the Taco EBV. If it is a true motor-driven valve it may be okay.

    If you are not adding to the system then one circulator and the zone valves should work fine. Understand that if the circulator fails there will be no heat anywhere whereas if you use multiple circulators you can have heat in the zones that have an operating pump. If you do add additional circulator pumps be sure to install isolation valves or isolation flanges on each pump, including the original pump.

    As shown on your drawing you have the circulators installed on the return side pumping into the boiler. If the expansion tank is connected to the boiler itself then you have a bad situation. The expansion tank should ALWAYS be connected on the suction side of the pumps. With multiple pumps this is usually best accomplished by having the pumps on the supply side.

    I do not know anything about "wireless" thermostats. I like wires.
  3. lmei007

    lmei007 New Member

    Messages:
    154
    Location:
    Maryland
    if the "supply piping" means pipes hot water flows from boiler to radiator and "return piping" means pipes hot water flows return to the boiler, the answer is yes. You can see from the "Heating Lines" diagram, there are two 1" pipes running from boiler to the end of the building. One is supply pipe and another (dot line) is the return pipe. On the way of those two pipe, there are several 1/2" pipes branches which are to/from the radiators.

    The Nonoflo tees are a special thing I need to pay special attention?

    Thank you, I will write down this.

    Yes, you are right. The current pump is in the return side and the expansion tank is connected directly to the boiler. But why that is a potential issue? It will be not easy for water flows from expansion tank to the system?

    Thank you, Furd.
  4. Furd

    Furd Engineer

    Messages:
    446
    Location:
    Wet side of Washington State
    The term is Monoflo, I'm not sure if you just slipped a finger and accidentally typed Nonoflo. If you have separate supply and return pipes that are not connected together anywhere except through the heaters then you do not have Monoflos.

    Do you have cast iron radiators or baseboard convectors? Or possibly a combination of the two or even something else?

    To answer the question about the placement of the expansion tank I suggest that you read the following pdf. file from Bell & Gossett. They also have a wealth of information available on their website that may help you in this project.

    http://www.bellgossett.com/literature/files/1195.pdf

    http://www.bellgossett.com/BG-Literature-English.asp
  5. lmei007

    lmei007 New Member

    Messages:
    154
    Location:
    Maryland
    Supply and return pipes are totally separated.

    I have cast iron baseboads and only have one old cast iron radiator on basement. No convectors, I think.
  6. Furd

    Furd Engineer

    Messages:
    446
    Location:
    Wet side of Washington State
    With separate supply and return lines you have a system that is perfect for zone valves.

    I suggest that you use valves that have a real motor and not a heat-actuated drive. You will likely need special thermostats to drive the motor-actuated valves although there are work-arounds.

    You could run this with a single circulating pump and if you install isolation valves at the pump and have a spare pump you could restore heat in less than an hour by swapping out a bad pump for the spare. Or, you could install two pumps with isolation valves and a changeover switch in which case you would only be without heat for as long as it took you to turn the valves and switch to the spare pump. Then again, circulator pumps don't fail that often so maybe the spare is overkill, only you can decide.

    I will state again that the cost of installing the thermostats and zone valves will probably be such that it will take several years, if ever, to recover that cost in reduced fuel consumption. However, if you want to do the zoning for comfort reasons then it can do a great deal of good.
  7. patrick88

    patrick88 Plumber

    Messages:
    836
    Location:
    Webster Ma.
    He has monoflo 1" pipe supply and return with 1/2" supply and return feeds to the cast iron heaters. I think there is some confusion.
    http://www.flickr.com/photos/lmei007

    please check out the pics they show what he has.
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,824
    Location:
    New England
    One thing to consider, and it may not be a problem, is the circulator after you shut off say all but one zone. It may need a bypass valve to keep the head in a proper range. Some can handle big variations, some can't, or the velocity might be too high.
  9. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    The things that people call "radiators", and the baseboard units that are installed in most hydronic and steam heating systems, are all convectors. They transfer heat by the passage of air over them by means of convection.

    Anything will radiate heat if it is warmer than the surrounding area but the radiation heat transfer is small compared to convection heat transfer.
  10. Bosun

    Bosun New Member

    Messages:
    89
    Location:
    Minneapolis
    Fewer Zones

    I would vote to simplify this plan, or just keep the whole place a bit cooler and use an oil-filled space heater where needed. Doing multiple zones will be expensive; you need a separate thermostat wired for each zone. You will need a valve (and likely a pump) fo each zone. Plus, are they easily split? Sometimes the same pipes feed most of the house--i.e. they aren't split right at the boiler. The parts add up. The labor will be costly.
  11. TMB9862

    TMB9862 New Member

    Messages:
    206
    Do they make monoflow fittings for PEX? With the price of copper this will cost thousands.
  12. carkingsllc

    carkingsllc New Member

    Messages:
    8
    how difficult would it be for you to install shut off valves right before each baseboard?

    will that work? I mean if you simply stop the flow through each heater with a shut off valve then you will be able to shutoff each room as needed? or is this far fetched.

    I have a very simuar set up in my house except i have inlet and outlets i dont have monoflow, but i have the exact same baseboards. and i have a 1500sqft ranch, in NJ.

    thanks for those bell & grossett links furd i leaned a lot from them and i think i can complete my install from what i learned there.
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