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  1. #1
    bezsenne's Avatar
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    charging r407c by weight



    Hi everybody,
    I am learning how to charge units now. Today I was charging heat pump with R407c. The service valve was on LP. The amount of refrigerant due to rating label is 900g. I used rothenberger roklima 4f, which charge the unit with bottle pressure. The bottle pressure was 8bar. In this conditions I charge only 280g.
    Please teach me what should I do now. Is it possible that the amount of refrigerant on rating label is wrong? I am wondering if i should run compressor to charge the full amount?
    Hope for tolerance reply since I am newbie in this area.



  2. #2
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    Re: charging r407c by weight

    Did you evacuate the system first?
    Were you charging liquid from the cylinder?
    Is it really cold where you are? Might have to warm the cylinder up first.

    Edit: If there's a liquid line valve or condenser schraeder valve, better to charge into there rather than the LP valve, but I doubt there is for a system that takes only 900g.

    R407c isn't big in australia, for all those wondering why I work on R22 systems all the time. R407c was only used by a couple of Daikins and a few euro brands like delonghi. Every other brand stayed with R22 until R410a come out a few years later, and of course there's hundreds of chinese units here (some mainstream western brands, but made in some chinese factory), that kept using R22 until about 2 years ago).
    Last edited by paul_h; 02-03-2011 at 01:52 PM.

  3. #3
    bezsenne's Avatar
    bezsenne Guest

    Re: charging r407c by weight

    Refrigerant was evacuated, one element was substitutet without change in heat pump construction. Then vacume was made, before charging.
    The temperature in a room in which the charging was made was around 20 Celsius degree.
    Renew:
    Is it possible that the amount of refrigerant on rating label is wrong? I am wondering if i should run compressor to charge the full amount?

  4. #4
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    Re: charging r407c by weight

    Is it a reverse cycle a/c or some other application?
    I've never had a problem getting 900g of liquid refrigerant into a split system heat pump.
    600-900g is a small system and never had a problem at 20C.
    edit: and as I asked before, did you charge refrigerant in the liquid state? You must do if using R407C, R410a, R404a etc anyway.

    You could do it for any fixed charged system too, I always do it with R22 systems for example.
    Last edited by paul_h; 03-03-2011 at 01:06 PM.

  5. #5
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    Brian_UK is offline Moderator I am starting to push the Mods: of RE Site Moderator : and general nice guy
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    Re: charging r407c by weight

    Rating label will be correct, you charging method is not.
    Brian - Newton Abbot, Devon, UK
    Retired March 2015

  6. #6
    bezsenne's Avatar
    bezsenne Guest

    Re: charging r407c by weight

    Well, refrigerant in the bottle is in liquid state.
    In the mean time i repare 3 units, when the charging stops, before whole amount was charged into unit i turn on unit. Then compressor work decrease the suction pressure and make it possible to charge with the amount from rating label.
    Is it correct method of charging?

  7. #7
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    Re: charging r407c by weight

    If it works then it is OK.
    Brian - Newton Abbot, Devon, UK
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    Re: charging r407c by weight

    Hi Bezsenne , Hi Btian and paul

    Bezsenne ,
    1) R407 is a mixture , you should charge liquid , if the cylinder is not equipped with a deep tube , you should turn it up side down to get the liquid.
    2) The system should be evacuated from the refrigerant it was inside and a vacuum must be applied, those decreasing the pressure in the unit to -1 Bar, so if the cylinder pressure is 8 bars , the deltaP would be 9 bars a you would charge.
    3) if the pressure in the system became equal to the pressure in the cylinder then no refrigerant will pass from the cylinder to the unit , you must creat a deltaP , either by heating the cylinder (not with direct fire , i've seen that happening for who might wonder), or by turning on the unit.
    4) keep charging until you reach the desired ammount.

    Best regards
    Engineering, sciences, math, physics and my brain will generate "not responding " soon

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