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.

Delta T

In a residential setting, what are the typical Delta T's used in the circulator-sizing formulas for the following types of loops:

1) System loop of CI Radaitors

2) System loop of copper-fin tube baseboard

3) Indirect fired DHW tank



  • Rodney Summers
    Rodney Summers Member Posts: 748

    1 and 2 is typically 20° dT. Probably NOT for the reasons you suspect either...

    # 3 has no design dT "standard." There are so many variables, e.g., if the well water is 38° and the indirect just filled and the boiler cold, we could see a 100° dT and that would be fine.

    If sombody's in the shower and the boiler is large, the dT could be 5°. That too would be fine.
  • hydronicsmike
    hydronicsmike Member Posts: 855
    HUH?? You answered your own question?

    GPM = Btuh / (deltaT x 500)
This discussion has been closed.