62
D
A
B
C
sG
G
lJ
F
E
H
?
aJ
Fig. 53
?
Secondary circuit flow temperature sensor
aJ
Secondary circuit return temperature sensor
sG
Secondary pump
lJ
3-way diverter valve for "Central heating/DHW
heating"
A
Liquid gas temperature sensor (IRT)
B
Condenser
C
Pressure sensor (ITC) for determining condensa-
tion temperature in condenser
D
Flow temperature sensor, secondary circuit
upstream of instantaneous heating water heater
(LWT)
E
Secondary circuit air vent valve
F
High limit safety cut-out for the instantaneous heat-
ing water heater
G
Instantaneous heating water heater
H
Drain & fill valve, secondary circuit
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
5700 542 GB
Maintenance
