Mitsubishi Electric CITY MULTI P500YMF-C Service Handbook page 72

Check Valves Block1
The refrigerant flow in the pipe 6, 7, 8 and 9 are depend on ON/OFF of the SV3, 4, 5 and 6.
Please confirm by LED monitor display.
You can open the cap of valve A, B and C, but 3 types of hexagon socket screw keys. The size is as follows.
* Closed torque : A : 1.7kg·m (0.17N·m)
–70–
B : 20kg·m (2.0N·m)
C : 13kg·m (1.3N·m)