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PONPC on Electric Boiler

Hilly Member Posts: 417
With this Electric Boiler setup, would this be considered PONPC and pumping away? With the confined space this layout would provide the tidiest look and least amount of piping, fittings, supports, etc. Seems to me like it would be proper enough. I figured the AS on the supply tapping at the warmer water would be most appropriate. There would also be ball valve and drain tap on the return side upstream of the make-up/fill. That would provide fast purging all entire system through the boiler.


  • hot_rod
    hot_rod Member Posts: 16,286
    You got it.

    A large Webstone purge ball valve up top just before the circ gives you purge and isolation in one clean valve. It also provides a port to inject cleaners or inhibitor chemicals.

    As long as the boiler is a fairly wide open vessel it becomes, with the expansion tank, the PONPC. Same way a hydroseparator or cast iron boiler. There is very low pressure drop in a wide open tank or boiler. So it becomes the PONPC regardless of where the tank connects on either return port.

    If it is and older system, iron pipe for example a dirt separator is a nice addition, add a magnet if it has, or could ever have an ECM circulator.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Hilly
    Hilly Member Posts: 417
    Actually my diagram has the red line blocking out a flanged isolation purge valve. If it was all available I would have piped the fill to a AS with flanged connection and sandwiched them altogether. Webstone makes so cool stuff.