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  1. #1
    Join Date
    Jul 2005
    Location
    Steeler country
    Posts
    66

    Chiller baffled!

    Could someone help me to understand the point of this. Here goes: We have two McQuay heat recovery chillers HSC079. On both units , the leaving condensor water lines start off 10 inches then reduces into a 4 inch butterfly valve then up to an 8 inch line. Theres also a short 4 inch bypass on the same inlet /outlet with a butterfly. Why would we want to use this bypass in summer. I can understand using it in the winter. I notice that the condensor delta is always 20-30 degrees. I also dont understand why were trying to maintain condensor supply at 67 either. I dont get the meaning of this setup. Am I the only one?

  2. #2
    Join Date
    Jul 2005
    Location
    Steeler country
    Posts
    66

    Additional info

    In regards to the above posting , there are two pneumatically controlled butterfly valves in this setup. From what I understand, when the chiller is running in the heat recovery mode the primary 4 in. valve chokes back the flow to increase the head pressure for heat recovery. My question is, shouldnt this valve be wide open during summer cooling, non- heat recovery usage when the chiller is in opration? When this valve chokes off flow our head pressures go way up and the condensor inlet/outlet water temperatures fluctuate anywhere from 20-35 delta T. Cant this potentially be hazardous? By the way, the condensor barrel is what they call a split barrel with half the barrel circulating tower water and the other half circulating low grade hot water uesful for fan coils and such. The hot water pumps are not in use during summer/cooling mode.
    Last edited by techreptdh; 07-27-2008 at 04:35 PM. Reason: spelling

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