Question about Refrigerant

[marc5180]

I have always thought that when a system is short of gas that is running on R407c or like , that if more than 10% has been lost then rather than "top it up" it should be recovered and recharged because you don't know which of the blends has been lost....but if that is the case then when you ( for example) charge a system with say 3kg from a a full cylinder then how do you know what percentage of each blend is going to be charged into the system...(hope that makes sense)

[taz24]

but if that is the case then when you ( for example) charge a system with say 3kg from a a full cylinder then how do you know what percentage of each blend is going to be charged into the system...(hope that makes sense)


You should always charge the refrigerant as a liquid.
That will stop any seperation.


taz.

[BigJon3475]

http://www.refrigerants.dupont.com/Suva/en_US/pdf/h47125.pdf

If your just interested in 407c and 410a Du-pont has the above info. I'm sure you could find other refrigerants as well. 1/2 the charge lost several times in a row and recharged with liquid 407/410 produce little to no ill effects depending on how many times it leaks out and is refilled.

You must charge blends as a liquid.

[Argus]

.


I have always thought that when a system is short of gas that is running on R407c or like , that if more than 10% has been lost then rather than "top it up" it should be recovered and recharged because you don't know which of the blends has been lost....

That’s what they tell you to do because the relatively high glide with R 407C, (about6.5 degrees) means that the vapour phase contains the 3 components in a differing ratio to the specified ratio for R 407C.

But the first thing, obviously, is to find the leak and fix it.


…...but if that is the case then when you ( for example) charge a system with say 3kg from a a full cylinder then how do you know what percentage of each blend is going to be charged into the system...(hope that makes sense)

It does make sense, and the unequal separation in the vapour phase applies equally to service cylinders.
The accepted wisdom is that the cylinder should be filled to its capacity each time you charge from it, rather than partially full, because this minimises the vapour content in the cylinder that is not in the correct mixture ratio.
Then you charge in the liquid state to maintain the correct mixture which will have the correct mixture within acceptable tolerances.
In reality, on a windy roof, this is easier said than done.

Small imbalances in the mixture will go unnoticed in most systems. You will probably loose more capacity through dirty filters than a slight imbalance in refrigerant mix.


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[NoNickName]

Blend changes titration only when the system leaks refrigerant at a temperature inside the glide range, aka distillation

[saharco]

If your just interested in 407c and 410a Du-pont has the above info. I'm sure you could find other refrigerants as well. 1/2 the charge lost several times in a row and recharged with liquid 407/410 produce little to no ill effects depending on how many times it leaks out and is refilled.

You must charge blends as a liquid.

i heard that in europe the are changing the 407 blends to 507 blends cause they seems to break up and cause frosting on the evaportors