Fan Control – No Vfd Or 1St Fan Vfd; Condenser Fan Control State; Saturated Condenser Temp Target; Minimum Target Value - Daikin Pathfinder AWV Series Installation, Operation And Maintenance Manual

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.
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 is equal to the base target, but constrained to a
calculated/selected range defined by the Minimum Target value
and Maximum Target value.
Base Target
Base Target (°C) = 0.979264 x OAT + 10.7
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 51: Fan Numbers for Each Fan Digital Output
# Fans 4 6
1 - 101
2
- 102
Fan
3 - 103
Output
4 - 104,106
#
5 - 105
6 - -
# Fans 4 6
1 201 201
2 202 202
Fan
3 203 203
Output
4 204 204,206
#
5
- 205
6 - -
IOM 1242-2 • PATHFINDER
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
Circuit 2
8 10
201 201
202 202
203 203,205
204 204,206
105,107 207,209 207,209,211
106,108 208,210 208,210,212
MODEL AWV CHILLERS
®

Minimum Target Value

Minimum Target value is designed to keep the compressor in
its operational envelope. This value is calculated based on
the pressure difference, pressure ratio and fan stage down
deadband.
First 10 minutes after compressor start:
Minimum Target = 38°C
After compressor has been running 10 minutes:
Minimum Target = Max (16°C, A, B) + Fan Stage Down DB
A = Saturated temperature of [Evaporator Pressure + 180
kPa ]
B = Saturated temperature of [(Evaporator Pressure +
101.325) x 1.6 -101.325]
After the first 10 minutes, the minimum range is gradually
decreased to the calculated value at a rate of 0.1°C/sec.
Maximum Target Value
Maximum Target value is designed to help keep the
compressor motor temperature within limits.
Maximum Target = Min (Condenser Target Max set point, C)
C = [Min (53, Saturated Evap Temp x 1.15 + 51.35) + 0.3 x
(compressor speed - 14)] – 6.5°C
12 14
101 101
102 102
103,105 103,105
104,106 104,106
107,109,111,113
108,110,112,114
12 14
201 201
202 202
203,205 203,205
204,206 204,206
207,209,211,213
208,210,212,214
62
C
IrCuIT
16
101
102
103,105
104,106,107,108
109,111,113,115
110,112,114,116
16
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