hello can you help??
i have one of the above on 407c with a 48 kw ahu on with 1 1/8" liquid line, the unit seems to run well on comps 1 and 3 (both on differant circuits) if i run comps 2 and 4 aswell the suction pressure drops eventually freeze the evap then unit stops as lack of air flow, i have checked gas charge and think it's right 10.5kg condencer 0.58kg per m over 20 m for pipe and estimeted 5 kg for evap have full sight glass no aparent blockages/ temp differances in drier on liquid line tev appears to be responding to temp change phail is connected correctly, filters clean, fan running correctly
pressures on 1 comp per circuit 4 ish bar suction with 16/17 bar ish liquid,
pressure on 2 comp per circuit 2.5/3 bar suction and liquid around 16/17 bar

scratching my head tried loads of other things too but runing out of ideas

please help my head is spining!