Hitachi RWM-(H)FSN3E, Service Manual

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5 Control system
SMGB0070 rev. 1 - 08/2011
125
5
Second water temperature control
The mixing valve is controlled to maintain the second heating supply temperature at the second heating temperature
set-point. The mixing valve position is calculated with a proportional integral action (P+I) control algorithm based on the
difference between the heating supply set-point and the heating supply temperature.
Zone 2: Low temperature (30~35 ºC)
Zone 1
system
Hydraulic
Separator
Second temperature
control
Secondary
water pump
Motorized
3way valve
To YUTAKI S system
To YUTAKI S
system control
The system control then decides how much to open or close the mixing valve to achieve the desired position for the valve.
CODE REF Description Default Value Range Steps Units
3-133 PB Proportional band of mixing valve 6.0K -0.2~20 0.2 ºC
3-134 IRF Integral reset factor of mixing valve 2.5 0.0~20 0.1 %
3-135 RTV Running time factor of mixing valve 140 10~500 10 sec
N O T E
Heating and cooling operation have same values.