STULZ E
2
SERIES CONTROLLER FOR PERIMETER SYSTEMS OPERATION MANUAL
38
at which the CW valve is fully open, or 100%. The max fan
temperature is the offset at which the fan speed reaches the
"Run Speed" value (typically 100%). At the default values of 3
degrees each, the CW valve position will be 50% open at 1.5
degrees above setpoint and the fan speed will be 85%, as in
halfway between 70% and 100%.
The CW to Fan ratio is to be used as a method of "tuning in" the
interaction of the fan and CW valve after the temperature offsets
are determined. A positive ratio value between 0% and 25%
increases the CW valve position by that amount while decreasing
the fan speed by the same amount. A negative value decreases
the CW valve position while increasing the fan speed. For the
setting of above 50% CW valve and 85% fan speed, a 10% ratio
will increase the CW valve to 55% and decrease the fan speed
to 76.5%. A -10% ratio will decrease the CW valve to 45% while
increasing the fan to 93.5%. The regular limits on the CW valve
and fan still apply. If the unit is in the dehumidifi cation mode, the
fan speed will be limited to the Dehum Fan Speed parameter.
5.5.6.3 Static Pressure Set-up
On units equipped for static pressure control, static pressure
should be set-up and enabled when commissioning the A/C
unit. The operating static pressure can only be set correctly after
the A/C unit is installed and operable in its intended location.
To set the static pressure, turn on the A/C unit and allow the
blower(s) to reach full speed. Then, call up the Service menu.
Enter the Service level password and scroll to the
Blower>Underfloor Static Pr screen. This screen is only
available when the controller is confi gured by the factory to
Underfl oor Static Pr
Static setpoint: 000
Start fan speed: 30.0%
Static sensor: 360
Fan out: 60.0%
monitor a static pressure sensor.
Make note of the current
miwg static pressure
value shown in the display.
Next, scroll up to the
Service>Blower>Blower
Setup screen (See Section 5.5.6.1). Adjust the Low Speed
value up or down accordingly to raise or lower the current static
pressure. Return to the Service> Blower>Underfl oor Static Pr
screen and observe the resultant Static sensor value.
NOTE:
The static pressure is the square of the fan speed. A small
change in fan speed will have a large effect on the underfl oor
static pressure.
It will be necessary to fine tune the static pressure by
repeating the steps of setting the Low Speed value in the
Service>Blower>Blower Setup screen and then checking the
static pressure result in the Service>Blower>Underfl oor Static
Pr screen. When the adjusted Low speed value produces the
desired static pressure, write down both the Low Speed value
and the current Static Sensor value as observed in the
screens. Then return to the Main Screen by pressing the ESC
key and turn the blower(s) Off by pressing the Enter ( ) key.
Underfl oor Static Pr
Static setpoint: 360
Start fan speed: 60.0%
Static sensor: 0
Fan out: 00.0%
Re-enter the Service menu and scroll to the
Service>Blower>Underfloor
Static Pr screen. Enter the
Static setpoint value that
appeared in the Static
sensor field and enter the
Start fan speed value that
was the fi nal Low Speed value.
The A/C unit will now operate using proportional control to
maintain the static pressure at the setpoint entered.
If the speed values are adjusted in the Service>Blower Setup
screen (Section 5.5.6.1), it will have no effect on the operating
fan speeds as they are now controlled by static pressure.
5.5.6.4 Modbus Fan Control and Data Monitoring
Fan kW Limiting
Limit Fan kW: No
Fan Totl Limit: 0.0kW
Prop:200 Int: 10
Err db: 4 Action:Rev
Fan Total: 0.0kW
Fan Avg: 0.0kW
PID Output: 0.0%
This screen appears if the controller is confi gured for Modbus
fan control with a Fieldbus expansion card. It allows adjustments
to fan kW limiting parameters. Limits total kW of all fans (sum).
P/I control parameters may also be adjusted.
Fan Data - Watts #1
#1 0 #6 0
#2 0 #7 0
#3 0 #8 0
#4 0 #9 0
#5 0 #10 0
Power Add: 0
Total Power: 0.0kW
Modbus Data – Watts
The real time power consumption in kW is displayed for each fan.
This display screen may be utilized to estimate the total power
consumption for the system while it operates. The operator must
fi rst enter a Power Add value which will be added to the real
time power consumption of both fans. The Power Add value
is the estimated sum (in watts) for the balance of the system
loads. I.e. power transformer, etc. The result is displayed in the
lower fi eld “Total Power:”.
Fan Data - RPM
#1 0
#6 0
#2 0 #7 0
#3 0 #8 0
#4 0 #9 0
#5 0 #10 0
Modbus Data – Fan RPM (view only)
Additional view only Modbus fan data screens appear after the
Fan RPM data screen. These data screens provide the following
information for each fan:
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