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Installing basement radiator

smooninc Member Posts: 2
edited October 2023 in Plumbing
Looking for some tech advice: we would like to add a radiator in our finished basement bathroom. The boiler is a gas fired hot water system, single zone, which heats the floor above, the risers are located in the ceiling and boiler is located in the adjacent room. So, can I simple tap into the S & R's close to the boiler with Monoflo or Venturi tees and use a thermosatatic control valve on the radiator supply? The bath room is only 32 sq ft.


  • Intplm.
    Intplm. Member Posts: 2,083
    edited October 2023
    For that small of an area needing heat, you can probably cut into the supply side of your heating system as close to the boiler as possible. Run a feed, and return right from the new fin tube radiator.
    If you have a mono/venturi system as you mentioned you will need to pipe that as well.
    Are you sure it's a mono-flo system? Series loop systems are a bit easier if you have that.

    Heck. If its that close you can probably skip the venturi tees all together.
    EBEBRATT-Ed Member Posts: 15,839
    Just tie onto the supply and return to the boiler. 1/2" copper is plenty large enough. Put a balancing valve on the supply in case you have too much flow and noise.

    This will only get you heat when the upstairs heats. That may or may not be enough. Leave a ball valve on the supply and return at the boiler connections in case you want to make it a separate zone later.
    Intplm.EdTheHeaterManAlan (California Radiant) Forbessmooninc
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,167
    edited October 2023
    What are the radiators like that currently operate your system? How are the pipes connected to the boiler. If there is one pipe that goes around the basement and both pipes from each radiator are connected to the same pipe, then you most likely have a MonoFlo® or Diverter Tee system. If there is a separate pipe for all the radiator supplies and a separate pipe for all the returns, then you have a parallel system or a reverse return system. That system does not require any special tees. There is also a design that is popular when using baseboard type radiators. That is called a series loop. Adding a diverter tee to a series loop may have some unexpected results that you will not like.

    In order to tell you the best way to add that bathroom radiator, we will need to know what type of radiators you already have, what type of radiator you want to add the the bathroom, and how the system is piped from the boiler to the existing radiators.

    Pictures will also help a lot

    PS. If the boiler is that close, you probably don't need any MonoFlo® tees even if you have a one pipe MonoFlo® system. We just need to see where the circulator is located on the near boiler piping.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • smooninc
    smooninc Member Posts: 2
    Thank you. Its a 2 pipe system, each cast iron radiator connects to the Supply & Return lines, 1" mains that reduce to 3/4" then 1/2" at the radiators. System works well, heats up fast, I'm probably overthinking this. Considering using a 2-3 ft wall mounted "radiant panel", as they are thiner and it a tight space.