Technical data

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6.4 potentiometer adjustments
6.4.1 limiting the output for heating operation
The nominal heat output for the boiler can be limited if required to any value between 42kW and
210kW for the Midimat 220 and between 63kW and 316kW for the Strata 3 330. The maximum output
continues to be available for domestic hot water production.
To adjust the limit:
● Press the red ‘reset’ button. On the lower line in the display, the flow temperature T1 of the sensor
S1 is displayed.
● Press the ‘service button’.
● For the limit to be adjusted the red potentiometer must be turned. The display shows the old value
to the left and the new value to the right ( – – means: max output).
● By pressing the ‘service button’ again, the new value is stored.
MRO3
Fig 6.3c
6.4.2 setting weather compensation
● If direct-on-boiler weather compensated flow temperatures are required, then ensure the (supplied)
outside air temperature sensor has been installed and DIP switch No 2 has been set to ‘on’
● The boiler is supplied with the compensation slope shown (fig 6.4a) set as default.
Note: The default slope is obtained when the red and blue potentiometers are set in the vertical position.
● If the default settings are not applicable to the needs of the system user, then the angle of the slope
may be changed by adjustment of either the blue or red potentiometers, or both.
Adjustment of the red potentiometer raises or lowers the flow temperature at low outside (design)
(-1°C) air temperature. Adjustment of the blue potentiometer raises or lowers the flow temperature at
the end point (high) (20°C) outside air temperature. Each potentiometer has the range of +20°C and
-20°C about the default point but with a limiting factor that the maximum flow temperature is 85°C.
See graphs following which show the range of parallel displacement of the compensation slopes.
Service ButtonDIP Switches