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  1. #1
    Join Date
    Sep 2007
    Location
    Yuma, Arizona
    Posts
    252

    Chilled water coil plumbing...

    The installers of a heating coil and a chilled water coil apparently installed them backwards at one of our buildings. This was brought to my attention by the engineer. The chilled water coil entering the coil is on the bottom (like I expected) but it is on the front or the face of the coil. The engineer says I can expect to see a 15% efficiency loss. The same goes for the heating coil. I believe they are going to "correct" this by supplying the coil from the top which is located on the back or rear of the coil.

    I believe this will be a loss of efficiency as well but I don't have any information to back this up as I am not a smooth talker like the engineer. He claims to have worked for Heatcraft and he explained to me the reasoning for wanting the chilled water to enter on the back side of the coil and not the front. He also explained to me why you enter from the bottom of the chilled water coil and not the top. Yet I believe they are going to enter the top of the coil even though it is incorrect.

    Question: I am pissed off and would like to see it corrected, but should I be?
    Is entering the top of the coil sufficient?

  2. #2
    Join Date
    May 2008
    Location
    Central Pennsylvania
    Posts
    443
    Rotaryfrk, You may want to conferm the the coil configuration is infact wrong with the manufacture before you change anything. I ran into this same issue about two years ago with a carrier air handler. I would have sworn that it was wrong, but I talked to several carrier engineers and they said it was designed to be installed that way, with the water entering the downstream side of the coil. I ran the system and everything was fine. Actually I slightly increased the gpm to the coil and decreased the chilled water temp to squeeze out as much performance as possible through the air handler. Ended up getting 73 tons of cooling from a 50 ton coil. Hopefully this might save you a few headaches but your situation may be different.

  3. #3
    Join Date
    Mar 2003
    Posts
    7,326
    coldest water to coldest air. Inverse for heating. engineer noty only knows how to drive trains, he knows a bit about hvac as well.

  4. #4
    Join Date
    May 2008
    Location
    Central Pennsylvania
    Posts
    443
    Yep, I'd think the reasoning is to obtain as much dehumidification as possible. Cooler air has a lower dewpoint so you need to hit it with the coldest water. My perticular situation was a two pipe system though so only one coil, works fine in heating as well.

  5. #5
    Join Date
    Feb 2006
    Location
    SouthEastern Virginia
    Posts
    1,077
    Flange is correct.This is true for air or water heat exchangers. The air leaving a cold coil should pass through the entering water component of the coil on the downstream side of the coil.
    It might get loud!

  6. #6
    Join Date
    Nov 2004
    Posts
    210
    Generally,coils should be designed for counterflow,which gives the best heat transfer.The air and liquid flow in opposite directions, so that the supply piping enters on the side the airflow leaves. good luck.

  7. #7
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,965
    Jim Brown 39

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