KEY RK-2001W4, Operation Manual, Page: 8 / 20

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domestic hot water system or the accumulative tank only are supported by the
regulator. If the additional pump is turned off or it works as the mixing pump, then there
is no possibility of changing the WINTER/SUMMER mode (the parameter is not
available).
CAUTION!!! If the heating system is not equipped with accumulative tank, then when
a failure of the boiler sensor occurs, the temperature of the boiler water exceeds the
maximum value or the boiler overheating takes place, the central heating pump will be
turned on regardless of the working mode.
5.3. Domestic hot water tank working mode (bacteria eradication program) [cu u]
– the regulator enables to activate the process of bacteria eradication in the domestic
hot water tank manually. After selecting the ‘d’ value, the boiler is going to reach the
temperature of 75°C in the domestic hot water tank. Once the temperature of 75°C in
the domestic hot water tank is obtained, the bacteria eradication programme will be
turned off automatically. The parameter is not available if the additional pump works in
a mode other than the domestic hot water mode.
CAUTION! To prevent the users from being scalded, the option of bacteria eradication
should be switched on at night time when the water is not taken from the domestic hot
water tank.
5.4. The temperature measured with the additional sensor [u50°] – the parameter
presents the temperature of the accumulative tank or the domestic hot water tank tem-
perature. If the additional pump is turned off or operates in the mixing pump mode,
then the parameter is not available.
5.5. The measured temperature of the exhaust gases [150°] – the parameter is
available when the household thermostat input is switched to measurement of the ex-
haust gases temperature. In such case the above mentioned temperature is displayed.
6. Setting the parameters – service mode.
Holding the OK button for over 3 seconds will cause the regulator to enter the
viewing and setting parameters of the service mode. To view the parameters use the
buttons marked with ‘+’, ‘-’. After you have selected the particular parameter, it is
possible to enter the mode of change by pressing the OK button. This is signalized
with the blinking of the set value. The change of the parameter will occur after
pressing the ‘-‘ or ‘+’ button. To confirm the set value, press the OK button. Then the
regulator enables the user to select the next parameter. If it is not our intention to
change the parameter value with the + or - buttons, then select [End ] and press the
OK button or wait about 1 minute – the regulator will leave the service mode and the
temperature of the boiler water will be shown.