Schreiber Chillers 1055 New - Manual (Page 46)

Input State: :0000 – manually input values
Return Temperature 2
Analog Output #1
Control State : AUTO / MANUAL
Input State: :0000 – manually input values
Condenser Fan Speed
Analog Output #2
Control State : AUTO / MANUAL
Input State: :0000 – manually input values
Damper opening
This controller has two-stage compressor settings, the discharge temperature for stage 1 and
temp rise for stage 2. These setting are located in USER SETTINGS screen. Stages cycle
ON/OFF is based on these settings. Discharge setting activates stage 1 which maintaining the
reservoir temperature to the set point.
There are two ways to activate stage 2. First, stage 2 is activated when the difference between
the water temperature of return #1 reading and water discharge temperature reading is above the
TEMP RISE setting. For example:
Setting point:
In this example, we ignore HIST. setting
Discharge: 47
0
F
Temp rise: 10
0
F
Water temperature reading:
Discharge: 50
0
F
Return #1: 63
0
F
Clearly, stage 1 is activated because discharge reading is above the discharge setting. Stage 2 is
also activated since the difference between return #1 reading and discharge reading, (63-50 = 13)
is above TEMP RISE set point. Temp rise set point is independent to unit, it is just a value.
However, the discharge setting is dependent to unit. Changing the
0
C to
0
F or vice versa does
change the value on the temperature reading on the system status screen.
The second logic that activates stage 2 is that the discharge temperature reading is above the sum
of the discharge set point and Temp rise set point. This logic ignore the difference in the
discharge temperature reading and return #1 temperature reading as stated above. For instance,
we will be using the same setting as previous example,