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  1. #66
    Join Date
    Jun 2013
    Location
    N. Canada
    Posts
    361
    Quote Originally Posted by VTP99 View Post
    Give it up ! You seem to have a hard time answering questions.
    Let me try again.
    A low-temperature, central rack system was short on capacity. Two people decided to replace a 10HP compressor with a 15HP model. They had monitored the original amp draw. When the compressor change out was accomplished, the rack was still short and the amp draw was unchanged.
    Why ?
    simple... DISPLACEMENT !!!!!!

    My friend, I agree that one of us has some difficulty understanding the written word.

    moving on, case closed.

  2. #67
    Join Date
    Jan 2010
    Posts
    6,060
    Quote Originally Posted by VTP99 View Post
    Consider R22 for a medium-temperature application. A popular Copeland Discus, in-line compressor is the 3DS1500. For a low-temperature R22 application, the compressor need only be a 3DS1000. This equates to a one-third drop in horsepower potential.
    Why so if the refrigerant is unchanged ?

    HERE'S THE ANSWER !
    The answer is that a low-temperature condition utilizes a thinner gas. In other words, it's specific volume has increased, which results in a density decrease.
    Seems all you know is DISPLACEMENT. How then in my previous post example, did the same 1HP compressor with the same DISPLACEMENT have three different Btu ratings ?

  3. #68
    Join Date
    Feb 2012
    Location
    NY
    Posts
    128
    Quote Originally Posted by SurreyStevo View Post
    Your idea of a time clock will fix it. But, you're just giving it an 'off cycle'. Maybe the high ambient temp is infiltrating into the case and forcing this unit to run for long periods of time without any air defrosts. I would consider ways to lighten it's thermal load like: Upgrading the lighting to LED or swapping out the old shaded pole fan motors for PSC fan motors. You could sell a customer on the fan motors just by comparing the Watt consumption.
    Which would also raise superheat. I have an 8' case on account which iced over during the recent heat wave in the north east. Figure all that humidity and heat made perfect conditions for ice making. Weather has cooled, we defrosted the coil, and it's running good. But it made me think that thermal isolation is very important when troubleshooting the cause of ice over.

  4. #69
    Join Date
    Mar 2013
    Location
    swan valley idaho
    Posts
    719
    i ended up putting a paragon 9000 clock with 2 fifteen minute defrosts durring the day, 2 1/2 hour ones at night 10pm, and 4am.
    Mainly because we now know i have the wrong and undersized condenser, and it really never shuts off on temp. Owners trying to get money together for new condensing unit.....

  5. #70
    Join Date
    May 2005
    Posts
    1,347
    kklobas how long has this system been in use?
    Let's give nukes a chance.

  6. #71
    Join Date
    Mar 2013
    Location
    swan valley idaho
    Posts
    719
    4 wks

  7. #72
    Join Date
    Mar 2013
    Location
    swan valley idaho
    Posts
    719
    Well getting back to this old case with known wrong compressor. Called today. Not cooling. Found pressures for 416a at 60 degree box 16 low, 140 high. Suction line 80 degrees. Subcool 12 degrees. I closed suction service valve on compressor and suction actually went up to 35 never pulled any lower in 15 seconds or so.

    Guess they finally have no choice now.

    Did suction go up because discharge valves also are leaking by ? I would have expected it to at least stay the same ?

  8. #73
    Join Date
    Jan 2010
    Posts
    6,060
    [QUOTE=kklobas;16373661
    Guess they finally have no choice now.

    Did suction go up because discharge valves also are leaking by ? I would have expected it to at least stay the same ?[/QUOTE]

    Well you could change out the valve plate. Your suction reed is bad.
    Pull the head and have a look.

  9. #74
    Join Date
    Mar 2013
    Location
    swan valley idaho
    Posts
    719
    I told them they need to get the correct 3/4 hp condensing unit. Stop wasting any more money on this. Federal said it needs 3/4 hp.
    I am curious why my superheat went so high compared to 3 weeks ago. I'm thinking drier plugged(had lots of bubbles with 14 degrees subcool) glass after drier. I tried warming txv bulb before i valved off comp. no change in suction pressure. Drier did not show a temp drop at all with fluke clamp.

    Recomended new 404a condenser and txv .

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