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Married Heating Separately or Jointly

HydroNiCKHydroNiCK Posts: 92Member
My friend has a two story house consisting of three apartments heated by three separate boilers. Each apt/boiler is piped independent of the other and has it's own meter. They each provide domestic hot water and radiant tile floors. He is changing out the boilers and is adamant on getting three new combi mod. condensing. Is there any benefit to piping the boilers into one primary loop? They would still have separate meters. I've been pondering :
A) variable primary
B)cascading a primary loop on outdoor reset and each apt would be secondary pumped zone.
Can I do this and would it be fair to all the tenants?

Comments

  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,795Member
    If the boilers are tied together you will have no way to make the tenants pay fro their own fuel.

  • Intplm.Intplm. Posts: 753Member
    There really is no benefit to piping the boilers into one primary loop. Unless you are planning to include heat in the rental agreement? Under your circumstances you seem to have all the utilities separated for each unit, so why make the change?
  • ZmanZman Posts: 4,885Member
    It would be less expensive to install and and maintain and more efficient to install 1 boiler and 3 BTU meters. The owner would have to read the meters monthly and bill accordingly.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • hot_rodhot_rod Posts: 11,443Member
    I like the BTU meter approach also. Are there indirects on each boiler now? Any other appliances on the gas meters?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • HydroNiCKHydroNiCK Posts: 92Member
    No other appliances attached. Hm Im going to checkout this btu metering. I actually have this copy of idronics im going to grab it and read through. If the primary loop is heated to a constant temp or on outdoor reset each boiler is contributing to the communal pot so to speak. Yes there may be standby heat loss but during heating season someone is always using heat. If all three apartments have pretty much the same heat loss, radiant loops, and heating habits then equalibrium might be attained. If two tenants raise and lower heat normally and one tenant keeps heat at a constant or abnormally high then someone might pay more than another. However, the amount of money saved do to condensing because of the piping arangement and or cascading might outweigh any noticeable difference since all parties are paying less than they used to under the old system. Lochinvar's Smart cascading alternates the lead and lag boilers every 24 hours in order to give all three boilers equal run time.
    I guess what sparked me thinking about this is the smallest combi boiler is still way oversized. The turndown ratio helps but wanted to know if piping arrangement would help more by at least saving money on pipe and electric ( ie variable primary) or using a primary loop on outdoor reset. Separate meters contributing to a single goal of a reduced heating cost. Because the btu metering is interesting but it doesnt help me condense. If there is no benefit to single piping arrangement the meter would save money by only needing to buy 1 boiler. Still it might not condense for each zone. Maybe with the upfront space and cost savings my friend would be more open to adding a tank.
  • GroundUpGroundUp Posts: 515Member
    The smallest combi is still too large for the DHW needs of 3 units? I don't think so- this is why combi units are usually not ideal. What is currently serving DHW needs?
  • HydroNiCKHydroNiCK Posts: 92Member
    > @GroundUp said:
    > The smallest combi is still too large for the DHW needs of 3 units? I don't think so- this is why combi units are usually not ideal. What is currently serving DHW needs?

    That doesnt make sense plus I never said that.. Who sizes combi boilers to dhw anymore? That's so 2002..
  • HydroNiCKHydroNiCK Posts: 92Member
    The smallest combi is too large for 1 apartment. Leave out the dhw part. The radiant is the only heat source. Its embeded under stone tile. The tenants crank up the heat. Return temps too warm.
  • Intplm.Intplm. Posts: 753Member
    edited April 11
    @HydroNiCK I find this to be a very good subject. But I still have some concerns about not keeping things separate. As a former renter and current long time landlord, keeping things separated for the tenants also helps the landlord. When you say above, "someone might pay more than the other". You might want to rephrase that to say someone (will) pay more and that can cause a lot of friction between the landlord and tenant.

    I understand the concern and cost saving ideas expressed above, but it can make for some strained relationships between the tenants, and or, tenant and landlord. Something I would not want to create and have to live with.

    Weighing the "cost" savings over time just doesn't work the way I see it.
    What does your friend think?

    (And i really like that Caleffi idea too.)
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,523Member
    One boiler, 3 indirects, and 3 zones. 3 heat meters.

    Each heat meter serves one appt and its indirect. Done.

    I bet that's cheaper than 3 boilers.
    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
  • JUGHNEJUGHNE Posts: 5,672Member
    What factors does the heat meter use to achieve the result?

    Time...temp...flow etc?
  • superdavesuperdave Posts: 148Member
    can you send photos of existing boiler room. Also what is the BTUs load per unit on heat and each unit has what for DHW 1 kitchen, 3-P bath, and laundry?? Also what state are you in and are there rebates in your area that might make very thing come together.
  • GroundUpGroundUp Posts: 515Member
    edited April 11
    @HydroNiCK oh but you did say that. I was simply asking for clarification and pointing out why a combi would be a poor choice.
    HydroNiCK said:



    I guess what sparked me thinking about this is the smallest combi boiler is still way oversized.

  • HydroNiCKHydroNiCK Posts: 92Member
    > @Solid_Fuel_Man said:
    > One boiler, 3 indirects, and 3 zones. 3 heat meters.
    >
    > Each heat meter serves one appt and its indirect. Done.
    >
    > I bet that's cheaper than 3 boilers.
    >

    Yeah, that could work. A few different things would work. I made a suggestion but he told me he doesnt want tanks. I explained everything to him and he understands more now than he did. However, him saying he doesnt want tanks caused me to think about this and thought it would make a good discussion and there are a lot of good brains to pick here. A couple of you said there is no benefit to piping boilers together. You may be correct. I agree with Intplm. But the two piping schemes I posed above putting the primary loop on outdoor reset or cascading and programming boilers to have equal run time seem like they would work and have some benefit Anything technically wrong with what i posed or why it doesnt provide cost savings?
  • HydroNiCKHydroNiCK Posts: 92Member
    > @superdave said:
    > can you send photos of existing boiler room. Also what is the BTUs load per unit on heat and each unit has what for DHW 1 kitchen, 3-P bath, and laundry?? Also what state are you in and are there rebates in your area that might make very thing come together.

    Kitchen and bathroom group, Laars Endurance ( dont like those things). They all rotted out. Do to neglect and annoying design.
  • LeonardLeonard Posts: 831Member
    edited April 13
    Nice thing about having separate boilers is each tenant has to pay directly to gas co, not landlord. That keeps tenant from coming to you begging to not pay for heat if he has financial troubles.

    With tenant billing from gas co you can wash your hands of it and say you have no control over it. A plus is usually by law utility co's can't shut off nat gas & electricity in winter to residential customers, so your pipes won't burst and YOU don't have to pay for heat to protect your building. Also potentially lets tenant pay you rent longer, instead having to pay gas co.

    Plus if tenant doesn't pay rent, you aren't put in position of also having to lose money paying their heat bill , just so your pipes don't freeze. Ruining your drywall and wood.

    If tenant knows the system they can stay rent free for ~3 months while your eviction paperwork slowly works it's way thru notice periods, courts and appeals processes. If you supply heat with rent , law usually says you can't shut it off just because tenant doesn't pay you.

    It's maddening to not get rent , pay for eviction lawyer, AND have to supply free heat for months while tenant leaves windows open all day for "fresh air". Same issue if electricity/water is included with rent, then vindictive tenant leaves lights on all day and night. and water running.

    Dad was landlord of OLD 2 apt house, inherited from his mom.

    Many ways a tenant gets in financial trouble. Sometimes a divorced? single mother gives $2000 to her ex to fight DWI arrest and stops paying the rent.
  • superdavesuperdave Posts: 148Member
    I agree with washing your hands and being the Bank we all know how that ends up!!
  • superdavesuperdave Posts: 148Member
    Any heat loss and pump head needed??
  • hot_rodhot_rod Posts: 11,443Member
    JUGHNE said:

    What factors does the heat meter use to achieve the result?

    Time...temp...flow etc?

    Correct, it calculates base on those three inputs.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • hot_rodhot_rod Posts: 11,443Member
    With the Caleffi system you have 2 addition inputs. Any meter that has a pulse output can be added and the controller records those meters also.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Intplm.Intplm. Posts: 753Member
    Hey @HydroNiCK . Why not send some pictures of the job if you can. Would be nice to have a look. You have sparked my curiosity. And I'm sure others would like to see this too.
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,523Member
    That meter is cool hot rod. The fact that it can also totalize other aux inputs makes it even more useful.
    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
  • mikeg2015mikeg2015 Posts: 792Member
    Small combi are great for small units because many of the newer ones have 10:1 or better turndown ratios so they handle small loads well.

    With Naviens at least, you have to read the fine print, if they often have a capacity restriction based on flow rates since they have a high pressure drop on the heat exchanger and use an internal pump with a limited flow rate.

    Unless you have 30+ delta T, you only get 40k out of them in many cases. But DHW, because EWT is so cold, you can still get 3-5GPM depending on which unit size. We are installing a lot of there for floor radiant on small cabins in rural areas, heated garages, and new homes based on low cost slab and post frame style construction.
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