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water tank needs for radiant system

Gilly184
Gilly184 Member Posts: 2
edited August 2017 in THE MAIN WALL
Hello all. New to the wall. I recently installed a one room 600 sq foot radiant system of AL-Pex made up of three 200 ft loops. Now i am at the point of deciding on a heating element and understand every 100 ft of 1/2" is about 1gal volume,so i am wondering if i can get away with a 10-15 gal hot water tank with expansion tank, circulator pump and manifold? i believe the size of this system would work for a standard hot water tank vs a boiler... am i correct?

Comments

  • Zman
    Zman Member Posts: 6,989
    The whole process should start with a heat loss calculation of the space. That is how you figure out the boiler size.
    I would use a small modulating electric boiler and utilized outdoor reset to maximize comfort and efficiency.
    Electric water heaters are for heating domestic water. Boilers are designed for heating systems.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Ironman
  • Gilly184
    Gilly184 Member Posts: 2
    thank you for the response. I was told that with such a small system, that a boiler would short cycle regularly and would make the system inefficient and shorten the life cycle. i am assuming that they make very small boilers that would fit this system once i calculate the heat loss?
  • Zman
    Zman Member Posts: 6,989
    Given the size of your system, I agree that it may not be a good fit for a gas burning boiler. Unless you have other heating needs, it will be expensive to install and will short cycle.
    Electric would work well for a small setup like that and yes they do make small modulating electric boilers.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Henry
    Henry Member Posts: 988
    Thermolec makes small boilers with outdoor reset:
    thermolec.com/en/productView.aspx?type=product&id=58
  • Rich_49
    Rich_49 Member Posts: 2,611
    Zman said:

    The whole process should start with a heat loss calculation of the space. That is how you figure out the boiler size.
    I would use a small modulating electric boiler and utilized outdoor reset to maximize comfort and efficiency.
    Electric water heaters are for heating domestic water. Boilers are designed for heating systems.

    With all due respect Zman . We know nothing about the construction of this smaller area and it's needs/ requirements . The Purist in me agrees with you about boilers for heat and water heaters for domestic water . The other me which is always at odds with the Purist thinks boilers are required for high temp applications while a water heater is quite adequate for low temp / low load applications . An electric boiler is not really anything more than an electric water heater without mass , Aye ?

    For instance , this space could quite conceivably be 15,435 BTUh at design with a 25.6 BTU per sq ft requirement and maybe it only needs 125* water . Would you agree ? If this is so there is no reason why a single element 4,500 watt element tanked water heater could not readily perform the duty required of it . The codes are slow to respond thus the continued resistance to adopt other , better technology based on individual systems and lower load buildings . While building science technology advances rapidly we continue to sit on the sidelines with old ideas .

    To determine this though we are in agreement that a room by room heat loss is required to actually eliminate the generalization and have a real discussion about a source .

    In the meantime , everyone could purchase something like this
    https://www.uponorpro.com/~/media/extranet/files/heating literature/radiant ready 30e/rr30e_insg_h220_0411.ashx?version=050320110848&version=050320110848
    or any number of other well made and designed electric products
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
    Zman
  • Zman
    Zman Member Posts: 6,989
    edited August 2017
    Rich said:

    Zman said:

    The whole process should start with a heat loss calculation of the space. That is how you figure out the boiler size.
    I would use a small modulating electric boiler and utilized outdoor reset to maximize comfort and efficiency.
    Electric water heaters are for heating domestic water. Boilers are designed for heating systems.

    With all due respect Zman . We know nothing about the construction of this smaller area and it's needs/ requirements . The Purist in me agrees with you about boilers for heat and water heaters for domestic water . The other me which is always at odds with the Purist thinks boilers are required for high temp applications while a water heater is quite adequate for low temp / low load applications . An electric boiler is not really anything more than an electric water heater without mass , Aye ?

    For instance , this space could quite conceivably be 15,435 BTUh at design with a 25.6 BTU per sq ft requirement and maybe it only needs 125* water . Would you agree ? If this is so there is no reason why a single element 4,500 watt element tanked water heater could not readily perform the duty required of it . The codes are slow to respond thus the continued resistance to adopt other , better technology based on individual systems and lower load buildings . While building science technology advances rapidly we continue to sit on the sidelines with old ideas .

    To determine this though we are in agreement that a room by room heat loss is required to actually eliminate the generalization and have a real discussion about a source .

    In the meantime , everyone could purchase something like this
    https://www.uponorpro.com/~/media/extranet/files/heating literature/radiant ready 30e/rr30e_insg_h220_0411.ashx?version=050320110848&version=050320110848
    or any number of other well made and designed electric products
    @Rich
    I absolutely agree. Thanks for the link to the Uphoner product. That is awesome!
    I almost made the water heater recommendation as it would likely be the right size. I guess I don't like to recommend electric water heaters because they have become the "go to" device for every knucklehead installer out there. I think the tiny foot print of the electric boiler is a real bonus.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    HVACNUT