andrews R18 Series, Technical Documentation Manual

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18IP22B
13
Temperature limit control
The hot water heater is standard supplied with a preset temper-
ature limit controller
set at 65 °C to prevent from scalding and
lime scale precipitation. When exceeding the preset level the
temperature limit controller will shut down the burners.
The design and operating principle of the R18 water heater
ensures that limescale precipitation is kept to an absolute
minimum when operating under the following conditions.
Water hardness in Maximum pH Maximum operating
ppm temperature in °C
0 - 80 8,4 90
80 - 250 7,6 85
250 - 350 7,2 80
350 - 500 7,0 60
Table 3 Maximum operating level
Where extreme conditions of water hardness exist, however
consideration should be given to the provision of water pre-
treatment.