Carrier AquaEdge 19XR Start-Up, Operation And Maintenance Instructions Manual page 23

40
35
30
25
20
15
10
5
0
0 10 20 30 40 50 60
GV_POS
Fig. 19 — Effect of SURGE DELTA TSMIN on
Surge Prevention
45
40
35
30
25
20
15
10
5
0
0 10 20 30 40 50 60
GV_POS
Fig. 20 — Effect of SURGE DELTA TSMAX on
Surge Prevention
60.00
55.00
50.00
45.00
40.00
35.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
0 10 20 30 40 50 60
GV_POS
Fig. 21 — Effect of SURGE LINE SHAPE FACTOR
on Surge Prevention
Tsmin=30
Tsmin=40
Tsmin=50
70 80 90 100 110
a19-1959
Tsmax=60
Tsmax=70
Tsmax=80
70 80 90 100 110
a19-1960
Shape factor
= -0.020
Shape factor
= -0.040
Shape factor
= -0.050
70 80 90 100 110
a19-1961
40
35
30
25
20
15
10
5
0
0 10 20 30 40
Fig. 22 — Effect of SURGE LINE SPEED FACTOR
on Surge Prevention
If ACTUAL GUIDE VANE POSITION is less than 30%, go to
Step 1. If ACTUAL GUIDE VANE POSITION is greater than
60%, then go to Step 3.
1. Do not change SURGE LINE SHAPE FACTOR from the
value selected by Chiller Builder (ECAT). Decrease
SURGE DELTA TSMIN in 1°F steps up to 5 times. Moni-
tor chiller for surge.
2. If ACTUAL GUIDE VANE POSITION is still less than
30% and Step 1 failed, increase the value of SURGE LINE
SHAPE FACTOR in steps of 0.01 up to 2 times. For exam-
ple, if surge is encountered when shape factor is –0.06,
increase the SURGE LINE SHAPE FACTOR to –0.05. If
this does not solve the problem, go to Step 5, even if
ACTUAL GUIDE VANE POSITION is less than 30%.
3. Do not change SURGE LINE SHAPE FACTOR from the
value selected by Chiller Builder (ECAT). Decrease
SURGE DELTA TSMAX by 1°F steps up to 5 times.
Monitor chiller for surge.
4. If ACTUAL GUIDE VANE POSITION is greater than
60% and Step 3 failed to eliminate surge, then set SURGE
DELTA TSMAX to 5°F below the value specified by
Chiller Builder (ECAT). Increase the value of the SURGE
LINE SHAPE FACTOR in steps of 0.01 up to 2 times. For
example, if surge is encountered when the SURGE LINE
SHAPE FACTOR is –0.06, increase the SURGE LINE
SHAPE FACTOR to –0.05. If this does not solve the prob-
lem, go to Step 5, even if ACTUAL GUIDE VANE POSI-
TION is greater than 60%.
5. If ACTUAL GUIDE VANE POSITION is greater than
30% but less than 60% or if Step 2 failed (with ACTUAL
GUIDE VANE POSITION less than 30) or if Step 4 failed
(with ACTUAL GUIDE VANE POSITION greater than
60), then perform this step. Do not change SURGE LINE
SHAPE FACTOR from the value specified by Chiller
Builder (ECAT). Reset SURGE DELTA TSMIN and
SURGE DELTA TSMAX to the value specified by Chiller
Builder (ECAT). Decrease SURGE DELTA TSMIN and
SURGE DELTA TSMAX in steps of 1°F up to 5 times.
Monitor chiller for surge.
If the chiller is equipped with a VFD and the drive does not slow
down adequately at part load, then the machine is likely operat-
ing at a point above the configured "software" surge line and the
machine is in surge prevention mode. Check for a surge protec-
tion message on the HMI. If the unit is not in a surge protection
state, then the ENVELOPE SPEED FACTOR may need to be
increased (more aggressive surge line protection) in combination
with a decrease in the SURGE LINE SHAPE FACTOR.
23
50 60 70 80 90 100 110
GV_POS
a19-1962
Speed Factor
=1.60
Speed Factor
=1.85
Speed Factor
=2.00