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CONTROL POWER
IMPORTANT: To ensure power to the heaters, make sure main
power to the unit and the compressor circuit breakers is always
on (except for servicing or prolonged shutdown). Since water
cannot be drained completely, add an appropriate amount of
inhibited glycol as noted for winter shutdown.
Proper rotation of condenser fan(s), pumps and compressors
MUST be verified. Consult the Controls, Start-Up, Operation,
Service, and Troubleshooting manual provided with this chiller
for correct procedure. If pump(s) have been removed for
trimming, verify that wiring is reconnected in the original
manner. Failure to follow these procedures may result in
damage to equipment.
Control power is obtained from the main power supply and does
NOT require a separate source. A toggle switch (marked Emer-
gency On-Off on the unit label diagram and by the switch) allows
the control circuit to be manually disconnected when necessary.
IMPORTANT: For 208-v systems, the primary connection tap
for all transformers must be changed. The factory default
setting is for 230 v. Failure to connect to the proper tap may
result in unreliable operation.
Step 6 — Install Accessories
ELECTRICAL
A number of electrical accessories are available to provide the fol-
lowing optional features (for details, refer to the Controls,
Start-Up, Operation, Service, and Troubleshooting book):
Energy Management Module
(Used for any of the following types of temperature reset, demand
limit and ice features):
•
4 to 20 mA leaving fluid temperature reset (requires
field-supplied 4 to 20 mA generator)
•
4 to 20 mA cooling set point reset (requires field-supplied
4 to 20 mA generator)
•
Discrete inputs for 2-step demand limit (requires field-sup-
plied dry contacts)
•
4 to 20 mA demand limit (requires field-supplied 4 to
20 mA generator)
•
Discrete input for Ice Done switch (requires field-supplied
dry contacts)
High Efficiency Condenser Fan
If outdoor ambient operating temperatures below 45°F (7°C) on
size 020-030 units or 32 °F (0°C) on size 035-60 units are
expected, refer to separate installation instructions for high effi-
ciency condenser fan.
Hot Gas Bypass Accessory
If hot gas bypass accessory is required, refer to unit Price Pages or
contact your local Carrier representative for more details. For in-
stallation details, refer to separate installation instructions supplied
with the accessory package.
Miscellaneous Accessories
For applications requiring special accessories, the following pack-
ages are available: external vibration isolation, temperature reset,
hail guard/security grilles, storage tank, wind baffles, and remote
evaporator. For installation details, refer to separate installation in-
structions supplied with these accessory packages.
CAUTION
Step 7 — Check Refrigerant Circuit
DETECTION OF FLAMMABLE REFRIGERANTS
When working with the refrigerant side of the system follow these
precautions. Ensure that the area is in the open or that it is ade-
quately ventilated before breaking into the system or conducting
any hot work. A degree of ventilation shall continue during the pe-
riod that the work is carried out. The ventilation should safely
disperse any released refrigerant and preferably expel it externally
into the atmosphere.
Under no circumstances shall potential sources of ignition be used
in the searching for or detection of refrigerant leaks. A halide torch
(or any other detector using a naked flame) shall not be used.
REMOVAL AND EVACUATION
When breaking into the refrigerant circuit to make repairs – or for
any other purpose –conventional procedures shall be used. How-
ever, for flammable refrigerants it is important that best practice
be followed, since flammability is a consideration. The following
procedure shall be adhered to:
- Safely remove refrigerant following local and national
regulations.
- Evacuate.
- Continuously flush or purge with inert gas when using
flame to open circuit.
- Open the circuit.
The refrigerant charge shall be recovered into the correct recovery
cylinders if venting is not allowed by local and national codes.
The system shall be purged with oxygen-free nitrogen to render
the appliance safe for flammable refrigerants. This process might
need to be repeated several times. Compressed air or oxygen shall
not be used for purging refrigerant systems. Refrigerant purging
shall be achieved by breaking the vacuum in the system with oxy-
gen-free nitrogen and continuing to fill until the working pressure
is achieved, then venting to atmosphere. When the final oxygen-
free nitrogen charge is used, the system shall be vented down to
atmospheric pressure to enable work to take place. The outlet for
the vacuum pump shall not be close to any potential ignition
sources, and ventilation shall be available.
CHARGING PROCEDURES
In addition to conventional charging procedures, the following
requirements shall be followed:
•
Ensure that contamination of different refrigerants does
not occur when using charging equipment.
•
Hoses or lines shall be as short as possible to minimize the
amount of refrigerant contained in them.
•
Cylinders shall be kept in an appropriate position accord-
ing to the instructions.
•
Ensure that the refrigerating system is earthed prior to
charging the system with refrigerant.
•
Extreme care shall be taken not to overfill the refrigerating
system.
Prior to recharging the system, it shall be pressure-tested with the
appropriate purging gas. The system shall be leak-tested on com-
pletion of charging but prior to commissioning. A follow up leak
test shall be carried out prior to leaving the site.
RECOVERY
When removing refrigerant from a system, either for servicing or
decommissioning, it is recommended good practice that all refrig-
erants are removed safely. When transferring refrigerant into cyl-
inders, ensure that only appropriate refrigerant recovery cylinders
are employed. Ensure that the correct number of cylinders for
holding the total system charge is available.
48
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