Toshiba Super Modulus Multi R410A

[Kirky]

Hi guys hope all is well.

Got a call out to a Toshiba Super Modulus Multi master and slave unit. On arrival found that the unit wasn't cooling but didn't have any faults on the controllers.

The system is made up of 7 indoor cassettes 1-4 feeding main seating area, 5 feeding meeting room with own controller, 6 feeding entrance area and 7 feeding chill out room with own controller. indoor unit 6 is on same controller as 1-4.

All controller temp setpoint settings were set up wrong 18 in heating etc.

Put all controllers in test cool and attached gauges. Compressors started on both master and slave outdoor units but fans only run at very low speed. Suction pressure 3 bar discharge 21 bar.

Switched over to test heat and fans start as normal unit seems fine heating indoor areas no problem Suction 33 bar discharge 26 bar.

Decided to check indoors units were clean and we didn't have any blocked filters. What I did find was that indoor unit 6 entrance area wasn't running checked power supply and had power into pcb checked all fuses on pcb which were fine.

The funny thing was that the rest of the system seemed to be working fine with all other areas maintaining a 20 degree set point. So basically the only evidence of a fault is the low speed condenser fans and indoor unit 6 not running. The controllers are not showing any fault codes and the rest of the systems seems OK. For some reason cassette 6 is being held off could this be causing the low suction pressure.

Any pearls of wisdom most welcome