Fujitsu WGYA050DG6 Design & Technical Manual page 113

72 SAFETY DEVICES
Circuit protection
High pressure protection
Protection form
Current fuse (Main PCB)
Safety valve
- (HU01 - 17) -
WG  A050DG  WG  A100DG  WG  G140DG 
Activate (at 3 bar or more): Safty valve open
Model
WGYK160DG9
20 A
Hydraulic unit / Split DHW integrated