Daikin Pathfinder AWV Installation, Operation And Maintenance Manual page 66

Condenser Fan Control
Condenser fan control will vary in operation based on the Fan
VFD Configuration set point.
Table 56: Condenser Fan Control Configurations
Fan VFD Control Type
Configuration
None Staging only
1st Fan VFD Staging and speed
control of 1st fan on
the circuit
All Fan VFD Staging and speed
control of all fans
Physical Fan Layout
Fans are numbered as shown below (top view of chiller). Fan
numbers start on the left side of the circuit, closest to the
control box when facing the control box.
Circuit #1 fans start at 101 and can run through 116 depending
on the number of fans on the circuit. Circuit #2 fans start at 201
and can run through 214 depending on the number of fans on
the circuit.
Figure 71: Fan Numbering Diagram - Representative
Circuit 1
Control
101 103 105 107 109 111
Box
End
102 104 106 108 110 112
NOTE: Number of fans vary by unit configuration
Condenser Fan Control State
There are only two control states: Off and Condensing
Temperature Control.
When the circuit state is Off or Preopen, condenser fan control
will be in the Off state. All fans will be off.
Fan Control – No VFD or 1st Fan VFD
Fans On Each Digital Output
The tables below show which fan numbers are on each of the fan digital outputs.
Table 57: Fan Numbers for Each Fan Digital Output
# Fans 4 6
1 - 101
2 - 102
Fan
3 - 103
Output
4
- 104,106
#
5 - 105
6 - -
IOM 1242-8 • PATHFINDER
Control
Mechanism
Contactors
Contactors and VFD
ECM/DC permanent
magnet motors on
each fan
Circuit 2
113 115 201 203 205 207 209
114 116 202 204 206 208 210
Circuit 1
8 10
101 101
102 102
103 103,105
104 104,106
105,107 107,109 107,109,111
106,108 108,110 108,110,112
MODEL AWV CHILLERS
®
When circuit state is Start, Run, or Pumpdown, the condenser
fan control will be in the Condensing Temperature Control
state. Fan staging and speed will be controlled as needed to
drive the saturated condenser temperature to the target.
Saturated Condenser Temp Target
There are two purposes to have a variable condenser
saturated temperature target:
a. Maintain pressure difference and pressure ratio
above low limit for compressor to run within
operational envelope
b. Achieve best performance at various conditions
The target value is displayed on the controller screen and is
equal to the base target, but also constrained to a calculated
range defined by the Minimum Target value and Maximum
Target value.
Base Target
Base Target (°C) = 0.979264 x OAT + 10.7
Target Values
Minimum Target value is designed to keep the compressor
in its operational envelope. This value is calculated by the
controller based on the pressure difference, pressure ratio and
fan stage down deadband.
First 10 minutes after compressor start, the minimum target is
38°C (100.4°F).
After the first 10 minutes, the minimum target range is
211 213
gradually decreased to the calculated value at a rate of 0.1°C/
212 214
sec.
If the chiller is configured with the WSE option and is operating
in the Hybrid Cooling Pulldown or Hybrid Cooling Modulation,
reductions in the target value should only be allowed at a
limited rate. The rate of change allowed for target reductions
should be 0.1°C every 30 seconds.
12 14
101 101
102 102
103,105 103,105
104,106 104,106
107,109,111,113
108,110,112,114
66
Circuit Functions
16
101
102
103,105
104,106,107,108
109,111,113,115
110,112,114,116
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