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Adding glycol to hvac chiller loop

Discussion in 'HVAC' started by bayoubud, May 22, 2019.

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  1. bayoubud

    bayoubud Senior Member

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    Need to add glycol to the chiller loop. After doing a lot of bleeding to remove air in the loop plus adding make up water to pressure the loop the glycol mix is too low. We have a valve on the suction side of the pump which we use to fill the system when drained but feel we get more air in the system by this method. Thinking of bleeding pressure off at the highest bleed valve and dropping in a bucket of glycol, then opening the bleed valve near the circulating pump in the er and gravity siphon glycol into the loop. Has anyone tried this method, thinking it would not allow much air into the loop? Thanks for any feedback.
  2. Capt J

    Capt J Senior Member

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    Best to use a pump to pump it into the system...…..lower the loop pressure to very little and pump in a strong glycol mix, then measure after it circulates a bit, and drop some and add water with the fill valve if needed to lower the concentrate.
  3. bayoubud

    bayoubud Senior Member

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    We have a two gallon expansion tank which limits the amount we can pump in with the loop closed after lowering pressure. What about opening the highest bleed valve to bleed off diluted glycol until pumping in the amount of concentrated glycol we need? Like you said we can always dilute down to the mix we want with make up water.
  4. Capt J

    Capt J Senior Member

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    Yeah, that would work.
  5. bayoubud

    bayoubud Senior Member

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    It did work, we had hardly any air to bleed.