Viessmann PLC VITOCAL 350-HT PRO Service Instructions For Contractors page 37

General hydraulic scheme
Pos. Designation
Flow switch (AC/NC cooling)
qO
DHW cylinder
eP
eQ Cylinder temperature sensor
Immersion heater
eW
Cylinder loading pump
eE
Heat exchanger, cylinder loading system
eR
Flow limiter
eT
3-way mixing valve
eZ
DHW circulation pump
eU
Cylinder loading system flow temperature sen-
eI
sor
Heating water buffer cylinder
tP
Buffer temperature sensor, top
tQ
Buffer temperature sensor, bottom
tW
3-way diverter valve, cooling mode
uP
Heat exchanger cooling
uQ
Cooling water temperature sensor
uW
Coolant buffer cylinder
iP
(cont.)
Pos. Designation
iQ
iW
iE
iR
iT
r-P
r-Q
r-W
r-E
r-R
r-T
r-Z
r-I
r-O
z-P
Cooling water circulation pump
Buffer temperature sensor, top
Buffer temperature sensor, bottom
2-way valve (heat source shut-off)
3-way mixing valve, low temperature mainte-
nance
Heat exchanger, residual heat
Circulation pump, residual heat
3-way diverter valve, residual heat
2-way valve (dry cooler shut-off)
2-way valve (heat source shut-off)
Pressure switch, residual heat
Return temperature sensor, residual heat
Dry cooler
3-way mixing valve, frost protection and return
temperature raising
3-way mixing valve, secondary high tempera-
ture maintenance
Diagnosis
37