R22 liquid or vapour?

[cretan]

I know with 404a systems they should be charged with liquid.Now with an air conditioner what is best to use?Liquid or vapour?

[coolments]

Hi There,

with R22 if you know what charge should be in the system then it would be quicker to weigh the refrigerant into the system in liquid form, if not you can carry out charging by vapour into the suction line, this can be a slow method but I like this way as you can see the change in the system as the charge becomes correct giving you experience in the symptoms that occur in units short of gas.

[sinewave]

There's only one proper way of gassing up kit and that's with a set of scales.

Pure Refrigerants may be charged in a gaseous state or a liquid state with liquid being far quicker.

If it's a blend then liquid only even if there is only a charging port on the low side only.

If charging in liquid form on the low side with the comp running then careful 'flashing' in of the liquid refrigerant is required if you want the comp to stay in one piece.

[coolments]

[quote=sinewave;108147]There's only one proper way of gassing up kit and that's with a set of scales.

Sorry mate I disagree, if it was say a domestic fridge, packaged unit or VRF maybe so if the charge is indicated on the data plate but for many other aplications weighing a pre determined amount in is not an option. For splits its still best geuss at the pipe work length and most dont account for bends when calculating.
all engineers should be able / taught to charge up a system with out using scales and actually look what the unit is doing I.E pressures, running currents, superheat, sub cooling, performance etc, how would you go on with a larger unit say Airedale DFA, a cold room or even an old AC system that has no receivers or accumilators installed with no gas charge indicated and it also being a critical charge.
I would also not recomend inserting liquid into the suction line of any system unless absolutely necassary, not only is it bad for the compressor but also if there is an acumilator before the compressor and the service valve used you could accidently end up filling it with liquid and leaving the unit slowly over charging its self as it boils off after you leave.

The thread is also specific question about R22 which is not a blend.

[philfridge]

[

quote=coolments;108205]
all engineers should be able / taught to charge up a system with out using scales and actually look what the unit is doing I.E pressures, running currents, superheat, sub cooling, performance etc[/quote
]
Some good points made although some blend refrigerants require to be charged in a liquid state into the suction line. This practise is acceptable as long as its done slowly preferably threw a capillary line or similar to stop large amounts of liquid sloshing into the compressor. Back to the thresd question and either way is ok to charge r22 system.