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  1. #1
    Join Date
    Oct 2008

    Default How to Install 1" thermostatic radiator valve on 1 1/4 Pipe


    We want to install thermostatic radiator valve on the original cast iron radiators in our 85 year old house. The existing piping to the radiators is 1.25 inch. The largest thermostatic radiator valve I can find is 1 inch.

    What are our options. Winter is on the way.

    Thank-you in advance

  2. #2
    Join Date
    Feb 2008

    Default Re: How to Install 1" thermostatic radiator valve on 1 1/4 Pipe

    Could you provide more info about your system---and also what the system is now doing wrong that requires TRVs.

    Is it a steam or hot water system---if it is steam, is it two-pipes or one pipe going to each radiator.

    If it is a hot water system 1 1/4" supply-return pipes indicates a series loop piping setup that is not compatible with TRV's (see heating help site on piping arrangements below).

    Click onto Loop hot water heating, and Diverter tee hot water heating to view the different piping arrangements used in these systems.

    Are you getting uneven heat, or too much heat from some rads and none from the others (steam system)??

    If so, check out the other parts of the system like the air valves on each rad, plus the main branch air valves in the cellar to get the system working in good form before you think of spending needless $$$ on a TRV.

    The articles below give some background on TRVs.
    Last edited by NashuaTech; 10-27-2008 at 03:45 PM.

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