Mercedes Benz Tourismo Bus Question

[madafaka]

Hello to everyone.
I have a newbie question. During vacuum on a MB Tourismo bus I have seen in the "glass window" where the oil level can be seen, bubbling! The bubles is humidity in oil, as the water boils?
Link with video: https://youtu.be/6JRuvn1W29c
Tank you

[frank]

Under vacuum process you are looking at refrigerant entrained in the oil boiling off. You can speed up the process by warming up the oil/compressor

[charlie patt]

You will also need to energise the sol valve on the roof pod otherwise a third of your system will not be vaced because of check valves I normally just run the engine to put heat into the comp the comp wont run because of the lp switch but the heat of the engine will address the above issue
Also if a bitzer comp remember to drain of front seal pipe