Overview Of Internal Components: Internal Unit - Viessmann VITOCAL 222-S Installation And Service Instructions Manual

Maintenance

Overview of internal components: Internal unit

K
H
G
F
E
D
Fig. 57
Flow temperature sensor, secondary circuit
?
(alternative positions)
Cylinder temperature sensor
%
aJ Secondary circuit return temperature sensor
Secondary pump
sG
3-way diverter valve for "Central heating/DHW
lJ
heating"
PWM signal, secondary pump
a:DB
DHW cylinder air vent valve for internal indirect
A
coil
Drain & fill valve, DHW cylinder: See following
B
chapter.
68
A
%
B
lJ
sG a:C] B
,
aJ
?
C
Instantaneous heating water heater with high
C
limit safety cut-out
Drain & fill valve, secondary circuit
D
E Service valve, internal unit: Schrader valve,
can be used in place of the external unit serv-
ice valve for pressure checks and evacuating
the refrigerant circuit; see page 50.
Liquid gas temperature sensor (IRT)
F
Flow temperature sensor, secondary circuit,
G
upstream of instantaneous heating water
heater (LWT)