Operating instructions

8
CONTROL ADJUSTMENTS
The leaving chilled water and hot water
temperature controls are set at the factory to the
Standard Specifications shown in Fig. 5. Your
Authorized Yazaki Service Provider can adjust
the setpoints with the ACT-3 maintenance
checker to accommodate step control on
multiple units or satisfy alternative design
temperatures, however, the differential is fixed.
The standard factory setpoints are adjustable
from 59.9
o
F to 41.9
o
F (leaving chilled water) and
122.9
o
F to 140.9
o
F (leaving hot water).
40.1 43.7 47.3 50.9 54.5 58.1 61.7 65.3
41.9 45.5 49.1 52.7 56.3 59.9 63.5 67.1
Chilled Water Outlet Temperature (
o
F)
•
Standard Rating Point Standard Control Settings
Fig. 5 TEMPERATURE CONTROL ADJUSTMENTS
CONTROL SEQUENCE
A built in microprocessor in the chiller or
chiller-heater controls the external pumps and
heat medium bypass valve (if installed) in
response to the cooling and heating load. The
operating sequence of each pump and the cooling
tower fan after start-up, during normal operation
and after a normal stop or abnormal shutdown is
shown in Fig. 6. It is important that the chiller or
chiller-heater have control over the pumps to
allow for controlled shutdown under normal and
abnormal conditions.
Capacity (%)
COOLING
100
75
50
25
0
Capacity (%)
Minimum Limit
Maximum Limit
HEATING
100
75
50
25
0
113.9 117.5 121.1 124.7 128.3 131.9 135.5 139.1
115.7 119.3 122.9 126.5 130.1 133.7 137.3 140.9
Hot Water Outlet Temperature (
o
F)
Minimum Limit
Maximum Limit