what is causing the sight glass to go white?

over the last couple of months i have had a odd reocuring problem that i cannot understand, three times and the only common thing is its always in cold weather cured ref leaks changed driers suitable torr when chargeing with a active
sight glass on 404 and 134 the refrigerant looks off white, when active when fully charged its clear its a dully off white so much so you can not sea the botom of the sight glass, good quality ref decent driers and if poss evaps had been warmed crank heaters on to hit a suitable torr any ideas something to do with the blends and cold weather :):)

You got me there at least Charlie.
I have not come across that situation either, an interesting post thanks!
Grizzly

Sounds like mineral oil with hfc refrigerants!

all three clearly marked with either 404a or 134 one c/room fitted aprox 6 years ago by myself never had a comp maintained by us the other two all comps marked up and id plates with oil grades no mineral oil on those two either but i am looking for ideas

If by any chance, you have used Chinese refrigerants, expect water in the system, run acidity test to be sure.

the ref comes out of a large supplier in bristol so i cant sea a issue there thats the 404 and the 134 comes from a different supplier again a main player to

sounds like moisture, you could always have an oil sample tested

Supposing your system is clean: The white may come from very fine droplets formed by oil+liquid refrigerant mixture.

Your oil or system was probably charged with a mixture of oils, with different viscosities or with foaming and anti-foaming agents.

Foaming agents are used to reduce noise from compressors.

Anti-foaming agents improve lubrication.

Manufacturers tend not to give much information on this.

Read this:
http://www.nucalgon.com/assets/prodlit/3-68.pdf

First u have to flush Condenser & evaporator With nitrogen with small amoount of gasoline then vaccum it properly. did u do that

one was a new system and the others i have history with there is no chance of mixture of oils since the ambients have warmed up i have not seen this problem again some how it must be related to the colder ambient when chargeing none of the systems had crank heaters?

should of said one system did not have a crank heater others had