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Radiant floor heating

Is it necessary to use a bronze pump or can I use a cast iron pump for circ in a PEX (wirsbo) floor system???


  • EinsiedlerEinsiedler Member Posts: 93
    open vs closed

    If you are using PEX pipe for infloor heating... I will assume that it is going on an "open system". as such, non-ferrous pumps must be used, so Bronze is the way to go.

    If this is on a closed system. Wrong pipe to use. it will allow oxygen to permeate into the system, causing several issues including "rusting" all ferrous components.

    I'd use PEX with OB (oxygen barrier). this allows you to go either way (open or closed) and allows for future installation of proper "Closed" system.

    Only use Cast Pumps on closed systems.


  • Hepex has an O2 barrier, so as long as you are not connected to an open system (water heater, no heat exchanger... which you shouldn't be!!!) you don't need a bronze pump.

    Aquapex, another Wirsbo product, does not have an O2 barrier and would require a bronze pump.

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  • G TwitchellG Twitchell Member Posts: 8

    I have a standard 50 gal water heater in the loop as a buffer/volume and I have HePex poured in the floor. I am using a TAKAGI tankless boiler/heater (190kbtu max) with no sidearm domestic hot water unit. I guess I can use the cast iron pump according to your reply.
  • EinsiedlerEinsiedler Member Posts: 93
    you have barrier pipe then

    you are good to go.
    Hepex is a great pipe c/w Oxygen Barrier.

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