D-EOMCP00104-14_01EN
Operating Manual
24/35
EWYD_BZ
Fan steps are activated or deactivated on the base of the staging table below
Steps staging
N° of fans per circuit
2
3
4
5
6
7
8
9
Stage
Active step
1
1
1
1
1
1
1
1
1
2
1+2
1+2
1+2
1+2
1+2
1+2
1+2
1+2
3
1+2+3
1+3
1+3
1+3
1+3
1+3
1+3
4
1+2+3
1+2+3
1+2+3
1+2+3
1+2+3
1+2+3
5
1+2+3+4
1+3+4
1+3+4
1+3+4
1+3+4
6
1+2+3+4
1+2+3+4
1+2+3+4
1+2+3+4
7
1+2+3+4+5
1+3+4+5
1+2+3+5
8
1+2+3+4+5
1+3+4+5
9
1+2+3+4+5
5.23.1.1 Fantroll in cooling mode
5.23.1.1.1 Control of condensing pressure
A stage up is executed (the next stage is activated) if the condensing saturated temperature (saturated temperature
at discharge pressure) exceeds the target setpoint (default 43.3 °C (110 F)) by an amount equal to a stage up dead
band by a time depending by the difference between the reached values and the target setpoint plus stage up dead
band (high condensing temperature error). In particular the stage up is executed when the integral of the high
condensing temperature error reaches the value 50 °C x sec (90 Fxsec). At the same manner a stage down is
executed (the previous stage is activated) if the condensing saturated temperature falls below the target setpoint
by an amount equal to a stage down dead band by a time depending by the difference betw een the reached the
target setpoint minus the stage down dead band values and the reached value (low condensing temperature error).
In particular the stage down is executed when the integral of the low condensing temperature error reaches the
value 14 °Cxsec (25.2 Fxsec). The condensing temperature error integral is reset to zero when condensing
temperature is within the deadband or a new stage is activated. Each fan stage will have its own adjustable stage
up (default 4.5 °C (8.1F)) and stage down (default 6.0 °C (10.8 F) ) deadband.
5.23.1.1.2 Control of pressure ratio
The control will operate to keep pressure ratio equal to a target adjustable value (default 2.8). A stage up is
executed (the next stage is activated) if the pressure ratio exceeds the target pressure ratio by an amount equal to
an adjustable stage up dead band by a time depending by the difference between the reached values and the target
value plus stage up dead band (high pressure ratio error). In particular the stage up is executed when the integral
of the pressure ratio error reaches the value 25 sec. At the same manner a stage down is executed (the previous
stage is activated) if the pressure ratio falls below the target setpoint by an amount equal to a stage down dead
band depending by the difference between the target setpoint minus the stage down dead band values and the
reached value (low pressure ratio error). In particular the stage down is executed when the integral of the low
pressure ratio error reaches the value 10 sec. The pressure ratio error integral is reset to zero when condensing
temperature is within the deadband or a new stage is activated. Each fan stage will have its own adjustable stage
up (default 0.2) and stage down (default 0.2) deadband.
5.23.1.1.3 Control of temperature difference
The control will operate to keep difference between the condensing temperature (saturated temperature at
discharge pressure) and evaporating temperature (saturated temperature at suction pressure) equal to an
adjustable target value (default 40°C (72 F)). A stage up is executed (the next stage is activated) if the pressure
difference exceeds the target pressure difference by an amount equal to an adjustable stage up dead band by a
time depending by the difference between the reached values and the target value plus a stage up dead band (high
pressure difference error).In particular the stage up is executed when the integral of the pressure difference error
reaches the value 50 °C x sec (90 Fxsec). At the same manner a stage down is executed (the previous stage is
activated) if the pressure difference falls below the target setpoint by an amount equal to a stage down dead band
depending by the difference between the target setpoint minus the stage down dead band values and the reached
value (low pressure difference error). In particular the stage down is executed when the integral of the low pressure
ratio error reaches the value 14 °C x sec (25.2 Fxsec). The pressure ratio error integral is reset to zero when
condensing temperature is within the deadband or a new stage is activated. Each fan stage will have its own
adjustable stage up (default 4.5 °C (8.1F)) and stage down (default 6.0 °C (10.8 F) ) deadband.
5.23.1.2 Fantroll in heating mode
5.23.1.2.1 Control of evaporation pressure
A stage up is executed (the next stage is activated) if the evaporating saturated temperature (saturated
temperature at suction pressure) is below the target setpoint (default 0 °C (32 F)) by an amount equal to a stage up
dead band by a time depending by the difference between the reached values and the target setpoint plus stage
