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Hy vent installed in tee on return?

99JT Member Posts: 1
I'm in the process of installing a hydronic unit heater in my garage which is being supplied by the boiler in my house which has a taco air separator. 

Question is would their be any benefit to adding a tee with a hy vent in the return line which is by far the highest point in the system


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    Might be the highest part of the system, but on the return, probably suck in air. If you have a micro absorber air elimination anywhere on that loop, pumping away, it will take care of any air problem after initial purging.

  • hot_rod
    hot_rod Member Posts: 21,835
    On the unit heater, should be a supply and return connection. Whichever is the highest one. If connections are at the same level on the unit, either will work

    As long as you have 5 psi or more at that vent, you should not pull air in.

    Assuming near boiler piping is correct, pumping away from the expansion tank

    A manual vent would work, you should only need to purge it once on start up if you have a good air purger, shown by Steve, at the boiler 
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream