Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

hot water ground up design

quack24 Member Posts: 74
hey guys im designing a heating system and would like some input
here is the preliminary design idea
it is going to be a hot water system with a combi boiler
it will be a mix of radiant flooring and radiators
basement will be tubing embedded in concrete 700 sq feet
1st floor will be radiant tubing stapled up with aluminum heat exchanger plates 700 sq feet
2nd floor will be home run steel panel radiators 600 sq feet
not sure how to set up the piping for a dual temp distribution
i was thinking about a manifold with a ecm circulator with trv valve installed on all radiators with 150 degree water and having the return water circulate through the radiant floors
i know im missing a lot of controls and details in this system any help is appreciated


  • Zman
    Zman Member Posts: 7,573
    Do a heat loss and size all emitters to run at the same low temp.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Zman
    Zman Member Posts: 7,573
    Siggy has dreamed up literally hundreds of mixing configurations over the years. I am sure they all work very well.

    When you look at a small system like yours, every mixing assembly has an associated price tag. I think you will find that it is simpler and more cost effective (definitely more efficient) to upsize the panel radiators and do a simple one temp system.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • bob eck
    bob eck Member Posts: 930
    Take a look at the Lochinvar Knight condensing gas boiler. Wall mounted model or floor standing model. Get a accurate heat loss and size boiler accordingly. Looks like this boiler control can do three different temps depending on the zone calling for heat. Also gives you priority for domestic hot water using a indirect water heater. The new Knight boilers come with a ECM primary pump. How many BTU will your smallest zone be? You might benefit from a buffer tank.
    If you can design all three zones to use the same temperature water then look at the Lochinvar Noble combi boiler. You still might benefit from a buffer tank with this model boiler. The Noble control will deliver only one water temp. If different zones take different water temps you can use mixing valves to get the lower water temps.
    There are other condensing gas boilers that have control that can also deliver different water temps. As far as I know most combi boilers will only deliver one water temp.
    Condensing gas boiler heat only or condensing gas combi boiler needs to be sized properly, piped correctly and vented correctly.
    This type boiler with proper maintenance can last you 15-20 years but once the parts warranty is over the controls and other parts that can fail are not cheap to replace.
    If you want a boiler that can last 30 plus years and still have 90% AFUE take a look at using the Weil Mclain GV90+ gas boiler.
    If you are looking for boilers 94%-95% to get gas utility company rebates then you will need to go condensing and not with the W/M GV90+ cast iron boiler.

    Find yourself a good professional heating contractor that can help you to design a good long lasting system for your house.