Example 2 - Reading Current Operating Modes
KEYPAD | DISPLAY |
| COMMENTS | |
ENTRY | I RESPONSE | I | ||
|
m H (Analog Inputs) - This subfunction displays analog inputs, if any. Enter m Fi , then use the q . The
c4 l
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TUE 15:45
LOCAL ON
COOL 1
0 ALARMS
2MODES LOCAL ON M O D E 8
Keypad has not been used for at least 10 minutes Rotating summary display appears on screen
There are 2 modes currently in effect
Unit is on by chiller on/off switch
Temperature reset is in effect
transducer supply voltage,
m(I bin p u t s ) - This subfunction displays status
(ON/OFF) of input switch where applicable. Status of dual set point switch, and demand limit switches 1 and 2 can be displayed. This is useful for problem diagnosis prior to us- ing the test function.
~~ (Outputs) - This function displays ON/OFF sta-
ity stage number. See Tables
Additional m provides the following information:
Percent of total unit capacity being utilized. Percent of each circuit capacity being utilized.
Demand limit set point in effect (can be any value be- tween 0% and 100%).
Load limit set point in effect. This is a CCN function for controlling operation of multiple units between 0% and 100% of total capacity of all units combined.
Status of each compressor relay. When a compressor is on, the number of that compressor is displayed. If a com- pressor is off, a 0 is displayed. For example: In a given circuit, if compressors 1 and 3 are running, and 2 and 4 are not running, 0301 is displayed for that circuit.
Load/Unload factor for compressors. This factor is an in- dication of when a step of capacity is added or sub- tracted. Its value can range from slightly less than
mF[ (Set Point) - This subfunction displays leaving
water temperature and leaving chilled water set point. If unit is programmed for dual set point, the chilled water set point currently in effect (either occupied or unoccupied) is displayed. If reset is in effect, the unit operates to the mod- ified chilled water set point. This means the leaving water temperature may not equal the chilled water set point The modified chilled water set point can also be displayed in the Status function. To enter the set point subfunction, de-
press mb[ and use the q to display modified leaving
chilled water set point followed by leaving water set point and actual cooler leaving fluid temperature.
F[(Temperature)F[- The temperature subfunction dis-
plays the readings at temperature sensing thermistors.
To read a temperature, enter Fi Fi , then scroll to de-
sired temperature using the m key. See Table 9 for the order of readouts.
flH (Pressure) - This subfunction displays suction,
discharge and net oil pressure at lead compressor of each circuit of unit.
tus of alarm relay, all fan relays, and chilled water pump relay. It also displays ON/OFF status of compressor unload- ers (if used). The position of each EXV (in percent open) can be displayed.
TEST FUNCTION - The test function operates the diag- nostic program. To initiate test function, the LOCAL/
To reach a particular test, enter its subfunction number, then scroll to desired test by pressing the ( key. Press B to start a test. Press q or q or H to terminate or
exit a test. Pressing the q key after a test has started ad-
vances system to next test, whether current test is operating or has timed out, Once in the next step, you may start
test by pressing H or advance past it by pressing I)I .
While the unit is in test, you may leave test function and access another display or function by pressing appropriate keys. However, a component that is operating when an- other function is accessed remains operating. You must
the component. Components with a timed operating limit time out normally even if another function is accessed.
Keypad entry riF[ allows the operator to make the
following checks by using m :
LID display check. Propezisplay is 8.8.8.8.8.8.8.8 . Operation of remote alarm.
Operation of condenser fans. Operation of chilled water pump.
Operation of EXVs. To drive EXV fully open, enter m m m (100% open). To drive EXV fully closed, en-
ter u (0% open).c
K e y p a d e n t r y.
compressor unloader operational tests.
During compressor operational tests, compressor starts and runs for 10 seconds. Compressor service valves must be open. Energize crankcase heaters 24 hours prior to performing compressor tests.
Since test function checks only certain outputs, it is good practice to also check all inputs and outputs accessible
through the status function. These are located at F\ F[ , m H, and mm (see Table 9). If keypad is not used
for 10 minutes, unit automatically leaves test function and resumes rotating display. See Example 3.
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