Installation Instructions

Troubleshooting | 13
6 720 815 281 (2014/10)MZ 100
5Troubleshooting
The indicator shows the operating condition of the module.
A number of faults are also shown in the display of the corresponding
user interface.
6 Environment / disposal
Environmental protection is a fundamental corporate strategy of the
Bosch Group.
The quality of our products, their efficiency and environmental safety
are all of equal importance to us and all environmental protection
legislation and regulations are strictly observed.
We use the best possible technology and materials for protecting the
environment taking into account of economic considerations.
Packaging
We participate in the recycling programmes of the countries in which our
products are sold to ensure optimum recycling.
All of our packaging materials are environmentally friendly and can be
recycled.
Old electrical and electronic appliances
Electrical or electronic devices that are no longer
serviceable must be collected separately and sent for
environmentally compatible recycling (in accordance
with the European Waste Electrical and Electronic
Equipment Directive).
To dispose of old electrical or electronic devices, you
should use the return and collection systems put in place
in the country concerned.
Use only original spare parts. Any damage resulting from
spare parts that are not supplied by the manufacturer is
excluded from liability.
If a fault cannot be rectified, please contact the
responsible service engineer.
Indicator Possible cause Remedy
permanently off
(at coding switch I)
Coding card on 0 ▶ Set the coding card.
Power supply
interrupted.
▶ Switch on the power
supply.
Fuse is defective
▶ When the power
supply is switched
off, replace the fuse
( Fig. 25, page 63).
Short circuit in the
BUS connection
▶ Check BUS
connection and repair
if required.
permanently red
(at coding switch I)
Internal fault ▶ Replace module.
flashing red
(at coding switch I
or temperature
switch II)
Coding switch to
invalid position or in
intermediate position
▶ Set the coding card.
flashing green
(at coding switch I)
Maximum cable length
for BUS connection
exceeded.
▶ Make shorter BUS
connection.
 Fault shown on
user interface display
▶ The user interface
instructions and the
service manual
contain further
information on
troubleshooting.
I/O controller or room
thermostats installed
without BUS
connection and the
DHW temperature in
the cylinder is not
reached within 3
hours.
▶ Operation alternates
between heating/
DHW
▶ Check heat exchanger
for limescale
deposits, descale if
necessary.
No BUS participant;
no setpoint received.
▶ Check BUS
connection and repair
if required.
Temperature sensor is
faulty.
▶ Replace temperature
sensor.
permanently green
(at coding switch I)
No fault Standard operation.
Table 10 Troubleshooting
0
1
2
3
4
S
Y
I
off
40
50
60
70
max
IIII
6 720 804 106-23.1O