So you want to design your own heating system?

mikefrommaine Posted By mikefrommaine, Dec 7, 2012 at 12:16 PM

  1. KenLockett

    KenLockett
    Feeling the Heat 2.
    NULL
    

    Dec 27, 2011
    495
    88
    Loc:
    Eastern Upstate NY
    Mike,

    The link above is an awesome primer! I'm most interested on calculations related to sizing circulation pumps for 20 Deg Delta T. I still wonder whether and when I should run my 3 speed circ pump at various speeds. I have always left it at the mid speed position but not sure if I could save energy and/or have more optimal transfer of BTUs if I ran at the low and high speed depending on load conditions.

    Ken
     
  2. jebatty

    jebatty
    Minister of Fire 2.
    NULL
    

    Jan 1, 2008
    5,252
    671
    Loc:
    Northern MN
    Due to the exponential relationship of flow to pump head, and depending upon the plumbing, a typical 3-speed circ (15-58 for example) will provide a pretty good increase in gpm when moving from L to M, but a much smaller increase in gpm when moving from M to H. A flow meter, or careful pump head calculations along with the pump curves, will show this based on your plumbing.
     
  3. mikefrommaine

    mikefrommaine
    Guest 2.
    NULL
    

  4. KenLockett

    KenLockett
    Feeling the Heat 2.
    NULL
    

    Dec 27, 2011
    495
    88
    Loc:
    Eastern Upstate NY
    Jim,

    In hindsight I wish I had plumbed a flow meter in series with the iwb circ pump loop but I didn't unfortunately. Do you have a turbine meter plumbed in with signal output or gauge reading only?

    On another note, bought one of those temperature controllers off amazon and am using the low alarm contact to provide me an alarm when it is time to reload the firebox. Little tricky because of loading variables but to add timing mechanism and better ability to monitor tx historically I bought an automation direct micro PLC on Friday with 4 inputs, 4 relay outputs, two analog inputs, and two analog outputs. Programming software is free. Bargain at $139. Also bought reset push button and alarm buzzer. Had circuit breakers and 24vdc power supply laying around. Temperature controller was $17 and even has the ability to transmit the PV to output effectively functioning as a TC to 4-20 mA signal conditioner for interface to the controller. I hope to ultimately implement all the boiler controls (designed with fail-safe mechanisms of course) into this system.

    Ken
     

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