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Hydrolevel VXT alternative install

Hello all,

In looking at the install picture for the VXT, they suggest using three isolation valves.  One of the valves is placed on input side of the VXT and the other is on the outlet side of the VXT.  Because of the location of both the H2O supply and subsequent feed into the wet return, my layout will look nicer if I change it from the suggested method. 

My question is this: do I need the isolation valve on the output side of the VXT or will it be just fine without it?



Note: I just realized that, in my drawing, one of my valves is labeled wrong.  The one feeding the VXT should be labeled as 'isolation valve'.


  • Rod
    Rod Posts: 2,067
    Stick to the Suggested Layout.

    Hi- Isolation valves are just that, they isolate! If you don't have a valve installed on both sides of the unit, it isn't isolated. One reason for  the valves and unions is so you can remove the VXT for serving or replacement without affecting your ability to add water to the boiler. Another reason is, that without the isolation valve on the output side, you couldn't service the VXT (clean the filter etc., having the line open) with the steam system operating unless the unit was above the "A" dimension.

    - Rod
  • MDNLansing
    MDNLansing Member Posts: 297

    Agree with MarkS. You need three valves to ensure you can add water when the feeder isn't installed (or if it's not working). Also, there might be times you water and divert the feeder, such as cleaning and filling. No matter what, 3 pipes means 3 valves.
  • Luv'nsteam
    Luv'nsteam Member Posts: 272
    I see it now..

    I hadn't thought about servicing the VXT.  Thank you - I will install the second isolation valve.

    All the best,

  • Luv'nsteam
    Luv'nsteam Member Posts: 272
    Another in VXT install question

    I would like to use a short flexible line to connect the feed water to the wet return.  This will help not just in dealing with the differences in fitting location (no ells needed) but I am also thinking about when the wet return gets hot and moves, the flex line will allow the movement.  Probably not required, but I like the idea.

    Do you see any problem with using a flex line for the feed water?

    Any suggestions for the type of flex line (the copper pipe is 1/2")?


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