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.

Disconnect hydronic loops, but keep using bouler's DHW coil

eddo Member Posts: 12
I'm replacing an old boiler with a combi boiler. I'd like to disconnect the hydronic loops so I can attach them to the new boiler, but since it'll take me a few days of part-time effort to complete the work I'd like to leave the DHW connected to the old boiler till the last minute. Is there anything wrong with that? No water in the boiler, just the DHW coil, or if that's not a good idea, any options for me?


  • GBart
    GBart Member Posts: 746
    make damn sure the expansion tank is still connected to the boiler you're running
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    You need water in the boiler, a working pressure relief valve, and the expansion tank connected as @GBart mentioned.
    I'd also disconnect the thermostat wires

    There was an error rendering this rich post.

    delta T
  • eddo
    eddo Member Posts: 12
    Thanks. So if I simply cap off the supply and return and keep everything else in place I should be good? Of course I'll make the boiler is filled after cutting those lines and capping them.