Bosch ZBR28-3A - 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

82 | Inspection and maintenance
Copyright (optional information)6 720 643 068 (2011/06)
14.1 Description of various steps
14.1.1 Calling up the latest fault (service function 6.A)
B Select service function 6.A (Æ page 71).
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.
Fig. 76 Filter in fresh water pipe
(combi boiler ZWB..-3A only)
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
(Æ 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
An overview of the faults can be found on
page 91.
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