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Vaillant Oil Boiler

dudley Member Posts: 1
I have a customer with a Vaillant oil fired boiler....about 20 to 25 years old. Model 7555. The Tridicator gauge is leaking onto the main operating control (Honeywell 8124), and needs to be replaced. He has the original installation and parts manuals, and has been in touch with Vaillant, and has been told that the part he requires is no longer available. The part number is 0355-5565. This looks to me like its just a 1/2" threaded gauge, but he's been told that it's attached to some sort of tube internally, and that the boiler won't run without it.....sounds strange to me. Any insight to this problem? Thanks.


    EBEBRATT-Ed Member Posts: 12,010
    Take it out and see. You can't just let it leak on the controls. I doubt it's more than a standard triadicator.

    Obviously there is no wiring to it so it cant control anything. Take a 1/2" plug and a new triadicator with you
  • Big Ed_4
    Big Ed_4 Member Posts: 1,884
    The gauge came in two parts . It was designed so one could replace the gauge without draining down boiler . The bushing section in the boiler self seals as you screw out the gauge ...
    I have enough experience to know , that I dont know it all
  • hot_rod
    hot_rod Member Posts: 16,320
    Like Ed indicated, that gauge goes into a well and can be removed.

    When the gauge screws in it pushes open a port to allow pressure readings.

    Watts made a gauge like that also, maybe they still do.

    Or use a 6 point socket, remove the brass well and install a regular 1/2 tridicator.

    Personally I'd rather have an accurate back connection gauge there, and a good thermometer elsewhere in the boiler or near piping.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream