Hi again

Just a small question this time

We have a DX system with TXV and compressor without capacity controll, there is liquid reciver without sightglass (sightglass is after reciver on pipe).
Lets say it works good on -10/+45*C.
But when we get condensing temp lower i get "bubbling" in sightglass.
I understand, that evaporating temp will go lower and the capacity of the system will all in all getsmaller, so i do not understand why i have bubbling in sightglass...

Thanks for replays, Marcin