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  • how to test a Expansion valve

    guest created 4 years ago 1 Member · 4 Posts
  • guest

    September 25, 2015 at 12:00 am

    how to test a Expansion valve hoshisaki R404 KM1300SAH

  • ectofix

    September 26, 2015 at 8:32 pm

    Juan, there’s no streamlined answer to your question.


    To test a TXV, you’d require some gauges, a clamp-on temperature probe, appropriate knowledge of what to expect of the stage of operation the ice machine is in while it’s running, access to that valve to make adjustments to it, then some REALLY good knowledge on how to adjust it and what to expect when you do.


    However, tweaking on an expansion valve is the last thing I’d do and isn’t advisable until you’re certain the unit has a proper refrigerant charge – which is weighed into the system to the exact ounce.  If it has a leak, then the machine WON’T have the proper charge.  You can’t know that without some form of leak detection (nitro & bubbles or electronic).  If no leak can be found, then the charge should still be checked by pulling it with a recovery unit, then evacuating the system and weighing a proper charge back in.


    You didn’t state your symptoms, but there are numerous other possible but rare issues with the ice machine refrigeration system which I have not mentioned.  However, about 80% of ice machine problems are related to malfunctioning WATER controls – NOT the refrigeration system.  So, make sure the evap plate and all water control devices/passages are clean, clean, CLEAN!


    There’s are no easy answer to your question with so little information provided.  Since you’re not a technician, I strongly urge you to call a reputable refrigeration technician to resolve your problem.  If you’ve never cleaned that Hoshi, you’ll need the proper chemicals on hand and follow the steps on the backside of the front panel.  Even that can be a bit intimidating, so a technician can do that for you too.  It’s about a four hour job and lots of labor if it’s really bad.

  • juan

    September 27, 2015 at 12:57 pm

    sorry maybe i dont explain myself alright english is not my language  but i just want to know the psi of my swing when i do my expansion valve test if is 7 to 5 psi swing on R404 or 10 to 7 psi i am a techinician so i dont need a one i just want to make sure i am doing it right.

    ps thanks

  • ectofix

    September 28, 2015 at 5:54 pm

    I see.  I had checked your profile before I’d said that and your profile stated “I am not a technician” – but then, I see you have deleted that.


    You’re talking about pressure swings from the TXV?  I don’t quite get that, but maybe someone else that has worked on ice machines more recently than I have can help you.  Whenever I tested TXVs and the refrigerant charge wasn’t in question, I tested those by monitoring the superheat it provides as it modulates. The only actual pressure I was concerned with was what it read upon leaving the evaporator.


    Hoshizaki Tech Support is quite knowledgeable and helpful.  Since your profile says you’re in New York, a phone call should be free, so I recommend that you give them a call.

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