Depress the Stop button to silence the alarm.
Marks on the indicator plate are for reference only and
are not calibrated in degrees.
4. Allow water bath to warm until contacts close. Depress
the Start button. Starters and Run light should energize.
Contacts should have a 7.2° F (4° C) differential between
opened and closed positions.
Cutout Temperature = Cut-in Temperature − Differential
5. Fill low-temperature cutout well (located on chilled wa-
ter nozzle) with heat conductive compound. Insert sens-
ing element into well.
NOTE: Usually low-temperature cutouts are preset at the
factory, with contacts set to open at 36 F (2 C) and to
close at 43 F (6 C).
Check Cycle-Guard™ Valve — (This valve is lo-
cated between refrigerant pump discharge line and solution
pump inlet.)
1. Place Cycle-Guard switch in MANUAL position. Cycle-
Guard valve should energize (denoted by an audible click).
2. Use clamp-on ammeter to check current in wire to Cycle-
Guard valve. Current reading should be 0.2 amps or less.
3. Place Cycle-Guard switch in AUTO. position. Cycle-
Guard valve should deenergize.
4. Place jumper wire between panel terminal RC
and
41 in the panel to simulate high evaporator level. Ter-
minal RO
is hot. Cycle-Guard light and valve should
energize.
5. Remove jumper wire between panel terminal RO
and
41 . Cycle-Guard light and valve should deenergize.
Check Solution Thermoswitch
1. Place jumper wire between panel terminal RO and ter-
minal 15 to simulate mid-level switch operation. Ter-
minal RO
is hot.
2. Place control sensing bulb on temperature cutout in wa-
ter bath maintained at ambient temperature. Slowly turn
switch adjustment screw clockwise until contacts close.
Cycle-Guard valve should energize. Note the difference
(if any) between actual thermometer reading and the read-
ing on the thermoswitch adjustment scale.
Using any temperature differential described above as a
correction factor, set adjustment screw to close at 47 C
(117 F). The switch has a fixed differential of 3° C
(5.4° F).
3. Remove jumper wire between panel terminal RO
and
terminal 15 . Cycle-Guard valve should deenergize.
4. Fill thermowell (located on the absorber strong solution
line between heat exchanger and spray header) with heat
conductive compound and insert sensing element into it.
Check High-Stage Generator Temperature
Thermoswitch —
The switch is factory set to open on
a rise in temperature above 170 C (338 F) and close on a
cooling below 163 C (325 F). Verify the approximate scale
position setting (170 C [338 F]) and closed switch contacts.
The switch range is 50 to 320 C (122 to 608 F).
NOTE: The switch operation setting cannot be easily checked
in the field. It requires a precise scale adjustment so do not
reposition if not necessary.
Check High-Stage Generator Pressure Switch
— The switch is factory set to open on a rise in pressure
above −20 mm Hg G (−0.8 in. Hg) and close with a
reduction in pressure below −205 mm Hg G (−8 in. Hg).
Verify the approximate scale position setting (−20 mm Hg G
[−0.8 in. Hg]) and closed switch contacts. The switch range
is −500 mm Hg G (−20 in. Hg) to 580 kPa (85 psig).
NOTE: The switch operation setting cannot be easily checked
in the field without breaking machine vacuum. It re-
quires a precise scale adjustment, so do not reposition if not
necessary.
Check Rotation of Solution and Refrigerant
Pumps
1. Place main circuit breaker in OFF position and reconnect
pump motor wires previously disconnected.
2. Place main circuit breaker in ON position.
3. Install compound pressure gage on refrigerant pump serv-
ice valve, depress Start button, and check pump dis-
charge pressure.
4. Place the main circuit breaker in OFF position and re-
verse any two motor power leads at starter to reverse pump
rotation.
5. Place the main circuit breaker in ON position and de-
press Start button. Compare the noise of both rotation di-
rections and check discharge pressure. Correct rotation is
the direction that produces the highest discharge pressure
reading and the least noise.
6. Repeat Steps3-5forrotation of solution pump(s).
7. To check chilled water pump and condensing water pump
rotation, refer to pump manufacturers’ instructions.
Check Capacity Control Operation (Fig. 21) —
The microprocessor-based controller is programmable for a
particular application by using its interface keys, display, and
selectable inputs and outputs. It can be set up for many dif-
ferent control variations. It is supplied originally configured
with default values for typical use, and is custom configured
in the factory when it is mounted in the chiller control panel.
Proportional capacity control valve positioning is usually
in direct relationship to changes in the leaving chilled water
temperature at a selected control temperature. Variations can
include such things as remote set point, dual set points, auto.
chiller start at a selected chilled water temperature, dual in-
puts, and computer control input and output interfaces.
The following checkout and adjustment procedure is for
standard use. The standard 16JT configuration set-up list, with
temperature measurement in degrees F, and 110 V, 60 Hz
control power, is shown in Table 4. See the UDC 3000 Uni-
versal Digital Controller product manual for specific de-
scription, configuration, operation, and troubleshooting in-
formation.
Do not depress the AUTO. TUNE and RUN/HOLD keys
or use the SET UP and FUNCTION keys for reviewing
the configuration without a thorough understanding of
their use because the configuration could be inadvert-
ently altered. Also, do not intentionally change any con-
figuration without a thorough understanding of both the
method and the resulting effects.
1. Verify factory customized configuration by checking the
controller displays: The letter F (Fahrenheit) in the up-
per left area; either an A (automatic control) or MAN.
(manual control) in the upper right area; and the actual
temperature at the sensor in the middle right area of the
display.
The lower display will show the letters SP (set point)
and the set point temperature when in the A (AUTO.)
mode, and the letters OUT (for output) and a value in
the range of 0.0 to 100.0 (percent output signal to the
23
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