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Thread: Prep Tables

  1. #14
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    Apr 2010
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    Charleston, WV
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    25
    I use Digimon 3 from Refco with low loss fittings and I do understand the principles of Zeotropic and Azeotropic refrigerants and I always try to put the left refrigerant in my 5' hoses into my low side will in operation. Thanks for the info

  2. #15
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    Sep 2008
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    Quote Originally Posted by Bolling View Post
    The unit uses 134a and required 8,75oz, I put in 8.9oz because of the hoses. I really do appreciate the input from all of you because if I don't know it I want to learn it and nothing beats answers from experienced Techs as far as I'm concerned.
    I have always used 1oz of liquid refrigerant per 3 feet of 1/4" hose as a guide. The densities of refrigerant vary, so that may not be precisely accurate, but it is close enough for most equipment that we service, so adding an extra .15 ounce wasn't enough.

    1.6 psi on the low side for a medium temp unit is more than a bit low. I have to say undercharge/restriction.

    Assuming that you had a 1/4" hose connected to the liquid line, I would add refrigerant as I described above and look for about a 15# suction. If you add the extra 1 - 1.5 oz refrigerant and the pressure remains low, I'd look hard at a cap tube and new drier.

  3. #16
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    Western PA
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    Quote Originally Posted by Bolling View Post
    I use Digimon 3 from Refco with low loss fittings and I do understand the principles of Zeotropic and Azeotropic refrigerants and I always try to put the left refrigerant in my 5' hoses into my low side will in operation. Thanks for the info
    If you are adding additional refrigerant to the system to compensate for connecting your hoses, DO NOT do this on small, critically charged systems.

    You will overcharge them.

  4. #17
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    Apr 2010
    Location
    Charleston, WV
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    25
    Appreciate the help I also thought restriction and not blockage because after recovering,vaccuming and wieghing in a new charge into the low side my high side rose along with the charge so I tought restriction- new dryer and cap but they called in another person to say over charge (don't know how) and I moved on to the next call.

  5. #18
    Join Date
    Apr 2010
    Location
    Wake Forest, NC
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    35
    When replacing a filter dryer on a small refrigeration system, go back with a solid core dryer, not a copper spun. R134 and R404 are notorious for clogging cap tubes, and the solid core dryer will do more to prevent that.

  6. #19
    Join Date
    Oct 2008
    Location
    mid-Tennessee
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    730
    Hey Iceman, how do you distinguish the difference in the two types of driers? Is it a difference in the part number? I've always used what is stocked in my van since I usually have one the same size and connection as the one I'm replacing. Will the guys at the parts counter know the difference?


    "You never know what others don't know." -

    If I can't laugh at myself...then I'll laugh at YOU! -

  7. #20
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    Sep 2008
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    Quote Originally Posted by ECtofix View Post
    Hey Iceman, how do you distinguish the difference in the two types of driers? Is it a difference in the part number? I've always used what is stocked in my van since I usually have one the same size and connection as the one I'm replacing. Will the guys at the parts counter know the difference?
    Just stock Sporlan driers and you will have nothing to worry about.

  8. #21
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    Apr 2010
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    Wake Forest, NC
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    Quote Originally Posted by jpsmith1cm View Post
    Just stock Sporlan driers and you will have nothing to worry about.
    Ditto

  9. #22
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    Apr 2010
    Location
    West Virginia
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    On tables that have the frost line around the cold compartment without a evaporator that has a fan in it, you will have lower pressures, and it may seem like a restriction.

    If you have a restriction and you let the system run for awhile the head pressure will actually go low, as the refrigerant condenses and the suction pressure will go even lower because of less head pressure to force the liquid refrigerant through the cap tube.

    If you measure the charge in you can add a little incase the scale is off or you hold gauge set different (this will mess you up, for sure)

    I always hook the gage set up to the bottle, system, and then tape the manifold to something so I do not move it.
    Then flush the refrigerant in on the High side (assuming you had to pull the system down for vacuum).
    I also have gauges for 134, 22, 409a, 404a as these are the most common refrigerants I use.

    On these and in general, if you do not find a leak do not add refrigerant.

    On under counters they almost always have the discharge line in a coil of some type in the condensate pan, always look for leaks there first, then in the evaporator (on fan models) on the end were the suction line exits, do not know why but 90 percent of the evap leaks I find are there.

    condensers are almost always cover with link or clogged, condenser fans will 60 percent of the time quit working after you clean the condenser coil because they have been running under low load for so long.

    current relay and start capacitor are high percentage of failures.

    Jim

    edit,
    Remember if a system takes 9 oz of refrigerant and you put in 11 just to make sure you will be overcharged by 22 percent.
    These small compressors will be overloaded this way and still run for quite a while.

  10. #23
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    Apr 2006
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    109

    Emerson driers are better

    Never Assume Anything

  11. #24
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  12. #25
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    Aug 2007
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    Winter Haven, FL
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    Quote Originally Posted by jpsmith1cm View Post
    Have never had a sporlan drier fail.

    Have had Alco/Emerson driers disintegrate and plug up the system.
    Now that you mention it, I cant think of a sporlin drier that came apart..Always those blue bastards...

  13. #26
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    Western PA
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