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  1. #1
    Join Date
    Oct 2008
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    UK
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    oversized compressor?



    Hi guys got a problem with a infrico pizza prep fridge. The customer had the compressor replaced by an engineer. The previous compressor was a Tecumseh AE4430 on R134a, the one he fitted is a AE4440 on R134a. The cabinet is working and cooling down to 3 degrees but the dryer is red hot even in a cold room, so when the kitchen gets hot the fridge starts to struggle and compressor is turning off on overload. When running from start the suction pressure is around 15psi. The condensor is clean and the condensor fan is working fine, i upgraded the fan from a 18w to 25w to see if it made much difference but it didnt. The gas dosent seem to be condensing. The difference between a AE4430 and AE4440 is only 1 or 2 CC so could this cause a condensing problem? or does it sound like a blockage in condensor? Could this be rectified without replacing compressor (maybe fitting larger condensor coil), any advice will be greatly appreciated, thanks in advance!



  2. #2
    Join Date
    Apr 2006
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    UK
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    Re: oversized compressor?

    hi northdude

    if you can give a bit more info would be good

    discharge pressure
    discharge temp
    liquid line temp
    suction pressure - 15psi
    suction temp

  3. #3
    Join Date
    Oct 2003
    Location
    Belgium
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    Re: oversized compressor?

    Replacing by a stronger fan will not help you, only consume more power.

    Air in the system?
    Wrong gas charged?
    Blocked cap tube?
    Overcharged?

    We need indeed more figures?
    It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.

  4. #4
    Join Date
    Oct 2004
    Location
    uk
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    56
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    Re: oversized compressor?

    more than likely wrong gas in system. r134a on the compressor doesn't always mean it should be 134a in the system. check model plate of cabinet and start with recovery, pressure test and evacuation before recharge with correct amount as on plate.
    please report back and supply details of subcooling and superheat.
    does the capillary look new?

  5. #5
    Join Date
    Jul 2011
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    United States of America
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    59
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    Re: oversized compressor?

    The new compressor is 4000 btu at 45degrees farenheit, vs. the old compressor of 3000 btu. I have installed this exact compressor to replace many smaller capacity ones like your old compressor. No problems. Yes you will have less subcooling, but the tecumseh aea4440 is an economical unit to purchase. I recommend that you install a TXV. It will really help in performance.

  6. #6
    Join Date
    Jul 2010
    Location
    NTH.QLD Australia
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    62
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    Re: oversized compressor?

    High liquid/vapour temperature in liquid line makes efficiency drop, yet at 15 psi, or -10C there abouts boiling temp in evaporator is too low. Not a balanced system if gas is R134a. Discharge temperature must be stinging hot! Larger fixed speed compressor on capillary system will decrease compressor life, and adding larger condenser won't solve problem as refrigerant flow through capillary will slow and have full liquid feed to evap BUT, suction pressure will drop and compressor will still get too high superheated vapour. Compressor is still going to run too hot.. Mike...PS. I've got sore red eyes from a bad case of the flu and my customers already think i'm on the "funny weed".., so go easy on me .. Where is the icon for kicking the bucket??
    To the optimist, the glass is half full. To the pessimist, the glass is half empty.

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