Benchmark ZWB 7-29 CC1 Installation And Servicing page 95

Specified CH flow temperature from TA... programmer exceeded
Check
If outside-temperature controlled programmer (TA...) is connected to boiler:
• The anti-cycle time is adjusted by the programmer to the suit the system.
• The factory setting for the anti-cycle time (3 min.) and the heating mode hysteresis setting, if applica-
ble, are deactivated.
• In cyclic mode, the switching of the boiler on or off is subject to a time delay in order to prevent diver-
gence between the average CH flow temperature and the specified CH flow temperature.
As a result (depending on the heat draw), the specified CH flow temperature is briefly exceeded.
In extreme cases, it can happen that the burner does not switch off until the maximum CH flow temper-
ature is reached even though a lower CH flow temperature has been specified.
1.
B Press button
B Select service-function 2.7.
Read off status of automatic anti-
cycle time (0 = Disabled, 1 = Ena-
bled).
B Select service-function 2.4.
2.
Read off anti-cycle time setting
(0 ... 15 min).
Hot water has unpleasant odour or is dark colour
Check
This is generally caused by the formation of hydrogen sulphide by sulphate-reducing bacteria. Such bacteria are
found in water which is very low in oxygen and live off the hydrogen produced by the anode.
1.
2.
7 181 465 346 GB (03.02)
.
Failure identification procedure
Action
B Note the setting of the temperature controls
and .
B Disable automatic anti-cycle time, i.e. change
setting to 0.
B Set anti-cycle time as required, e.g. factory set-
ting 3 min.
To return to normal function mode:
B Press buttons
and
B Regulate the temperature control
temperature control
positions.
Action
B Clean the hot water cylinder.
B Replace the sacrificial anode.
B Heat cylinder to a temperature ≥60˚C
B Replace magnesium sacrificial anode with
impressed-current anode.
The conversion costs are payable by the operator!
simultaneously.
and the
on the previously set
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