by Harry
(Oslo,Norway)
I have installed 2 unit Mitsubishi hara 6,6kw in the same time one in 6 meter long and other 2 m piping.
both of them had charged from factory R410A after installation they were working good on heat mode.
But after 3 days both of them stop heating any more. on service suction valve pressure is 150pis
and the valve is very heat. the liquid valve is not warm at all . it seems refrigerant flow has blocked some where in system.
NOTE..In this case I didn't use vacuum pump for pipe. I just screwed open hot valve and evacuated by suction side valve then I screwed open suction line .