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View Full Version : crankcase on or off.....


klobber
01-11-2010, 03:04 PM
would you leave the crankcase on then vacuum the system or vacuum then turn crankcase on before charging with refrigerant????
Grizzly
01-11-2010, 03:32 PM
Hi klobber.
I assume you actually mean whether to Vacuum with the crankcase heater on or not?
Warming the oil will help release any refrigerant trapped in the oil.
The choice is yours, personally a lot of times I actually use the vacuum pulled to suck the fresh oil into the sump.
Of course that is Dependant upon the size and type of system you are working upon?
The choice is yours. If it contains oil and has been open to the elements for any length of time then Heater on!
Cheers Grizzly
Grizzly
TrentMcDonald
04-11-2010, 07:33 AM
Well the main reason you vacuum a system out is to remove noncondensibles out of the system right. Keeping it on and heating the oil i would have thought also helped boiled off moisture.
Grizzly
04-11-2010, 07:56 PM
Well the main reason you vacuum a system out is to remove noncondensibles out of the system right. Keeping it on and heating the oil i would have thought also helped boiled off moisture.

True but as I said dependant upon the "works" having been carried out.
You would not want the heater on if there was no oil n the system, would you.
Further more with most modern synthetic oils, if the system has been opened long enough for them to have absorbed moisture.
Then they should be changed.
In ideal circumstances, all you would do is encourage any refrigerant within the oil to boil off.
Prolonging the time required to achieve the the target vacuum pressure.
The choice is yours!
Grizzly
bill1983
04-11-2010, 09:27 PM
some manufacturers recommend no power to system under vacuum apparently due to the risk of explosion. i have never understood this and have always worked on the same basis as the previous posters. you should always try to raise the temperature of the system to a level conducive with the prevention of ice formation. when under a vacuum, ice can form at relatively high temperatures, ie above 0. with the f-gas rules preventing us from effective triple vacuum, system temp/ambient temp has become more important and if needed should be artificially raised.