Liquid line frosting

[Takeshi]

I've noticed on quite a few modern air con. units that the liquid is very cold or starts to forst slightly:confused:
The unit runs fine etc, its just I've noticed that this only happens on modern units, mainly Fujistu etc.

[Brian_UK]

Are you actually looking at a liquid line ?

Quite a few units expand the liquid inside the condensing unit and not at the evaporator.

[Bones]

hey takeshi,

what model fujitsu's were these? were they running on 410a or 22?

i have seen a few of the first generation 410a units here (ast24 and 30LBAJ) frosting suction pipe, but this was only on units installed with less then the recommended minimum pipe run of 5m.

[Slim R410a]

Frosted liquid line = undercharged system.
Fujitsu themselves state this in a manual or another.

You can always see this after fitting a split past its factory charged length before adding the additional g/m. After letting it run for a couple of minutes the liquid line will frost.

[Takeshi]

Its definatly the liquid line - you can see the drier in the pipe run. I'm pretty sure its 410a - but it blows out lovly cool air etc, and has the right signs of a proper charge.