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Bad radiant in Seattle

Paul Pollets
Paul Pollets Member Posts: 3,656
I've seen dozens of these installs over the years...they may vary in equipment but all use the potable hot water heater as the heat source.The Rinnai tankless connects to the Heat Box for mixing and distribution. In this case, the mixed temp was trying to heat (1) fan coil unit in the basement and (3) loops of staple-up without plates on the upper level. The thermostat for the Basement was installed 3 feet directly above the FCU. Shall we say short-cycle? Non-barrier AquaPex was used for all distribution. The setup requires an RPZ backflow device, but none was installed.

FYI, I refused to do any work on the system, unless it was replacement. I referred the owner to the local Rinnai rep as I don't want the liability for this system working correctly.


  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 16,490
    But he got a good price.

    Right, Paul? That's all that matters, isn't it?
    Retired and loving it.
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,239

    Or maybe he made a small investment in a big price?

  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    The Price is Right

    Ahhhh, yes. But this is no game show....The price was too low for the builder to refuse. Now all the townhomes are plagued with yukky systems.
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,537
    Not radiant

    But I saw another tankless failing as a boiler in Locust Valley NY today. Using it as a backup to a solar DHW/Heat system. Unfortunately the distribution is hydroair and the Rinnai can't get the water temp up enough at outdoor temps below 20*. The electric tankless did but at a cost of $1600/month! Very bad application of solar in a high temp system
    To learn more about this professional, click here to visit their ad in Find A Contractor.