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Adding Glycol to closed loop system

bob58bob58 Member Posts: 1
I am trying to find the proper procedure for charging Propylene glycol to a closed loop system.


  • EricAuneEricAune Member Posts: 431
    edited October 2009
    Pump it in,

    I'm not sure I have the best way, or any way different than what other guys are doing.  Most of my systems are closed loop, I always use Webstone isolation flange sets with the drains for this very reason. 

    Start by flushing and filling the system to rid of air.

    I simply calculate the amount needed, have a sump pump in a five gallon bucket and an empty five gallon bucket for the drain water.  Pour the glycol into the pump bucket, pump in while return water is captured in the empty bucket.  I always figure for about 10% more glycol; as the glycol level lowers in the pump bucket you will have to switch the drain water hose to the pump bucket and some mixing will occur.  Top off pressure with hose and nearby water supply.

    This may not be the most expedient, or common way but it works and the tools needed are low cost.
    "If you don't like change, your going to like irrelevance even less"
  • hot rodhot rod Member Posts: 7,080
    a cleaner first

    get a hydronic cleaner fluid and run it in the system first. A dirty system will compromise the glycol.

    Buy pre-blended glycol or use DI deionized water to blend the glycol with.

    You will need purge valves in critical locations to purge out the fluid while pumping in the glycol.

    Some guys use compressed air to assure all the old fluid id flushed out. do it zone by zone to speed the flush process.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
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