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Capping a Tankless Coil

JC_5 Member Posts: 2
I currently have an Axeman Andersen Boiler (originally oil, now gas)with a tankless coil for DHW. To improve the DHW situation, I am considering adding another zone and an 80 gallon indirect tank. I have been doing lots of research on this an it seems simple enough to do on my own, I just have one question that hasn't been clearly answered by what I read; the pipes into and out of the current coil, are they simply capped off or are they treated differently (although I dont see how)
I am hoping to avoid this situation althogether by replacing the heating plant as I add the indirect tank, that is a budget issue though.


  • Guy_6
    Guy_6 Member Posts: 450

    I would not recommend capping the pipes of the defunct coil, as you may have pressure issues on the coil if capped. I have always left them open, or removed the coil and put a blank plate on the opening.
  • ChasMan
    ChasMan Member Posts: 462

    I heard if you try and remove the old coil you risk putting the boiler into the FUBAR pile due to bolts breaking off etc. Do you think this would happen even with My lil Slant Fin with stainless steel bolts?
  • J.C.A._3
    J.C.A._3 Member Posts: 2,981
    Which is why.....

    All tankless designs should have studs and BRASS nuts. Any coil that has ever been installed by me always geta a generous helping of an anti-seize compound also.

    I would just abandon the coil in place. No way should it be capped. That's just asking for trouble. As long as the gasket is holding, it should be fine. Chris
  • soot_seeker_2
    soot_seeker_2 Member Posts: 228

    Stainless steel bolts usually come right out. It would be nice to take the old coil out, as a leak down the road in it can give a headache. Don't go throught too much trouble if you dont have a blank plate and gasket. You may buy them only to find the bolts woun't come out. Stainless usually does though.

    Don't cap the old coil! Any moisture in it that flashes to steam will make a bomb. BOOM!

    How about running the supply water through the coil to preheat it? We do that when adding a gas hot water heater to a job that formerly had a coil.

    Just a thought.

    Long Beach Ed
  • David Sutton_6
    David Sutton_6 Member Posts: 1,079
    23 yrs.....

    and hundreds coils change and repaired and have not tossed a single one. if you willing to tackle a project like that you should be tooled up and ready for anything, Grinding wheels, taps and dies drills with GOOD bits properly sized, i have a welder with a portable rig i can call if realy needed. Have thing things in place and rady to go .I think they should all be replaced with indirects but there still here and need to be worked on by pro's....David

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • chapchap70_2
    chapchap70_2 Member Posts: 147
    I agree with the other postings

    I was just reading an old Crown boiler manual. The manual states that if you abandon the tankless coil, the coil should be drained and left open to atmosphere.
  • JC_5
    JC_5 Member Posts: 2

    Drain and left open, I think that is the way to go. This unit seems to be way too "intergrated" into the boiler to mess with. I really don't want to have to take off the shroud and get inside and deal with rusting parts and the like.
    I have been trying to find literature on this boiler, I cant find anything. I have time til I do this though.. I am not going to even attempt this until the weather warms and I dont need the heat(mid April or so)
  • bob young
    bob young Member Posts: 2,177
    relief valve

    if you cap the coil, make sure you have a tee with pressure reliel valve on the connection.
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