68
F
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.
G
Liquid gas temperature sensor (IRT)
H
Flow temperature sensor, secondary circuit,
upstream of instantaneous heating water
heater (LWT)
K
Secondary circuit air vent valve
L
Pressure sensor (ICT) for determining conden-
sation temperature in condenser
DHW cylinder drain & fill valve positions
A
B
C
Fig. 57
A
Closed
B
Open to drain the internal DHW line
C
Open to drain or fill the cylinder
Overview of internal components: External unit
Danger
Contact with 'live' components can lead to seri-
ous injury from electric current. Some compo-
nents on PCBs remain 'live' even after the
power supply has been switched off.
■
When working on the external unit, isolate the
system from the power supply, e.g. at a sepa-
rate MCB/fuse or a mains isolator. Check the
system is no longer 'live' and safeguard
against reconnection.
■
Prior to working on the appliance, wait at
least 4 min until the voltage has completely
dropped out.
Maintenance
Overview of internal components: Internal unit
(cont.)
5700 582 GB
Maintenance
