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constant circulation

sgriffis
sgriffis Member Posts: 4
Hi all,
I am restoring a house I just bought in northeastern NY. I removed the old forced hot air system and after a heat loss/gain calculation I bought a LP. Bosch greenstar contensing boiler (heat only). I have also been collecting/restoring old cast iron radiators.

What is the best system for this combination?

I keep hearing about constant circulation but when I mention it to local plumbers they stare at me like a deer in headlights. Am I crazy?

Comments

  • DZoro
    DZoro Member Posts: 1,048
    Not crazy. I personally have my home running on constant circ. Have not yet tried it fully on a customers home yet... Because it is my place and can play with the constant pump system, I actually do not even have a thermostat. Whole house is ran on odr, So far it is working great we went from 70* to -20* temps this year and the home stays a constant 68*. With the new high efficient pumps we have available to us and a Noble Combi, I figured this to be the most possible energy efficient way to do a heating system. So far it has not only been efficient but very comfortable. Most of my system is however radiant staple up and radiant concrete, mix, ranch home.
  • sgriffis
    sgriffis Member Posts: 4
    Thanks Dennis
    How should I best describe this to a plumber so u don't sound like a pain in the butt home owner?
    Are there any basic system drawings/schematic that I can show them?
  • Paul48
    Paul48 Member Posts: 4,470
    Yes.......You are crazy :smile: Let's back up and talk, a bit, about what you are doing with the heat loss info and radiation. If you do that wrong, you're doomed from the start.
  • DZoro
    DZoro Member Posts: 1,048
    @Paul48
    Yes there is a lot of homework to do. Like I said have not tried this with a customer. Having said that, the right customer who is willing to do the homework correctly, and a good contractor who is able to do his homework confidently is a must.
  • Boiler wrestler
    Boiler wrestler Member Posts: 43
    Aside from all the good advice you get here I would find someone who knows what constant circulation means to do your work. Soldering pipes is not the test to be a qualified installer. Unless you feel comfortable being the engineer on your project, you need to find someone who knows what their doing. Maybe use the "Find a Contractor" link.
  • sgriffis
    sgriffis Member Posts: 4
    I had a local plumbing supplier do the heat loss calculation and size up the boiler.
    As for the radiators iv been using a cast iron radiator btu calculate to match each radiator with each room based on 160° water
  • Paul48
    Paul48 Member Posts: 4,470
    @Dennis
    The "crazy" comment was just a joke aimed at the OP. He's got a great opportunity to have his system be really good. He's starting from scratch, and I just wanted him to focus on the "bones", first.
    Canucker
  • Gordy
    Gordy Member Posts: 9,514
    Some advice. If you are collecting old ci rads great.

    Some things to keep in mind. You have a modulating condensing boiler. To get the highest rated efficiency you need to get return water temps below 130 degrees the lower the better the higher the efficiency. It’s about condensing.

    With that being said oversize your radiation. This allows you to drop your supply temps down to lower your return temps.
    DZoro
  • Paul48
    Paul48 Member Posts: 4,470
    "As for the radiators iv been using a cast iron radiator btu calculate to match each radiator with each room based on 160° water"

    That's what I was afraid of.
  • Gordy
    Gordy Member Posts: 9,514
    Shoot for 150 at least. Since you're probably collecting what comes around. You need to strategize your radiator sizes, and placement. Make sure your radiation ends up balanced.

    By balanced I mean all rooms require the same water temp.
    So you don’t end up with one room needing 180, and another needing 150.
    DZoro
  • Gordy
    Gordy Member Posts: 9,514
    If this is a fresh start build. Home run the radiators to a manifold in the boiler room. A manifold with flow adjustment is best. Add trvs to radiators for individual control for setpoint. Now you got a system.
    Paul PolletsRomanGK_26986764589
  • Paul Pollets
    Paul Pollets Member Posts: 3,428
    I've been designing and installing constant circ systems for over 20 years. If the heat emitters are specified correctly and controlled by either TRV's (radiators) or a motorized mixing valve, the system works perfectly with even setpoints. Unfortunately, most contractors have limited experience using constant circulation, or the boiler controls that work this way.