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Mixing Radiation

JimRafferty Member Posts: 21
Customer would like to remove 3 standing CI rads from the second floor for decorating purposes.
The house is a mix of CI rads and CI baseboard on a single zone.
We can fit enough CI baseboard in each room to cover the load but the customer is asking about using Bud or Runtal type panel rads.
Has anyone had any experience- good, bad or otherwise- mixing panel rads in a CI house without breaking them out into a separate zone?
Thanks for your help!


  • Henry
    Henry Member Posts: 998
    I have a number of older homes to mix CI and others. It usually 50% more radiation and adding a thermostatic valve. It has worked for over 30 years.
  • mikeg2015
    mikeg2015 Member Posts: 1,194
    Need to over radiate it and add a thermostatic valve. Of if it’s in the room with the thermostat, then you need thermostatic valve. Probably is that it will still have less mass and will swing more in colder weather as it will cool off faster. Outdoor reset will help however to modulate water temps.

    But realistically, panel radiators prefer relatively constant flow and water temps matched to the load. Cast iron radiators are happy with intermittent operation and flow rates can vary widely. Just as happy at 10F as 30F delta T and any water temp.
  • Henry
    Henry Member Posts: 998
    Outdoor reset is a must also that I failed to mention. Using cast iron boilers it did not matter if they condensed. In the early 80s, I had a Viking Junior in my 1919 house that had outdoor reset. I used have the gas as my neighbours with no ill effect to the boiler. But I also installed all the original baffles including the folding cas iron one over the fire pit.