Description Of Various Steps; Calling Up The Latest Fault (Service Function 6.A); Fresh Water Filter (Only Combi Boiler Zwb; Plate Type Heat Exchanger (Only Combi Boiler Zwb - Bosch ZBR16-3A Installation And Service Instructions Manual

82 | Inspection and maintenance

14.1 Description of various steps

14.1.1 Calling up the latest fault (service function 6.A)

B Select service function 6.A (
An overview of the faults can be found on
page 91.
14.1.2 Fresh water filter (only combi boiler ZWB..-3A)
B Close cold water tap.
B Depressurize the cold water pipe.
B To access the filter remove the safety clip (step 1), pull
out the pipe (step 2), and remove the filter from the
pipe (step 3).
B If necessary, clean with plastic brush under running
water.
1
Fig. 76 Filter in fresh water pipe
(combi boiler ZWB..-3A only)
6 720 643 068 (2011/06)
page 71).
3
2
6 720 641 933-92.1o
14.1.3 Plate type heat exchanger
(only combi boiler ZWB..-3A)
If the DHW output on the combi boiler is significantly
reduced:
B Check filter in the cold water pipe for contamination
( Fig. 82).
B Depressurize the appliance.
B Remove plate type heat exchanger and replace
-or-
B Descale with descaling agent approved for stainless
steel (Grade 316-1.4401).
To remove the plate type heat exchanger:
B Unplug electrical connections.
B Remove hose from safety relief valve.
Fig. 77 Unplugging electrical connections / removing hose
from safety relief valve
B Loosen/remove pipe connections.
Fig. 78 Removing pipe connections
6 720 641 933-46.1O
6 720 641 933-47.1O
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