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170.600-IOM (JUN 11)
Page 14
MAINTENANCE
The operator must be familiar with the unit and this instruc-
tion manual in order to service and maintain the PowerPac
unit properly.
Before dismantling any portion of the unit, it is important to
make sure that the pressure in the unit or its components
has been equalized to atmospheric pressure. Parts to be
dismantled must not contain refrigerant.
Operator safety is improved by using gloves and face pro-
tection. It is suggested that a suitable gas mask be at hand.
It is useful to have spare gaskets available for replacement
use.
Only use the recommended Frick oil specified for your
PowerPac
™
unit. When handling refrigerants, oils, brines etc.,
personal safety and protection of the environment should
have a very high priority.
Use only the refrigerant for which the unit was originally
designed.
Before starting the dismantling/servicing process, remove
all main fuses, switch off all electric components on the
compressor/unit, and LOCK THE MAIN SWITCH.
Make sure that the motor cannot start up inadvertently.
Make sure that there is no over-pressure and no refrigerant
in the part to be dismantled.
Close all necessary stop valves.
Use the prescribed tools and check that they are properly
maintained and in good working condition. In explosion-proof
areas, use tools suited for this specific purpose. Also use
electrical protection equipment and tools suited for electrical
operation purposes.
Use only Johnson Controls original spare parts; other parts
may impair the safety of the compressor/unit.
TABLE 1 - EXCESSIVE CONDENSING PRESSURE
Cause
Insufficient water flow through the condenser
Fouling in the condenser
Overheated cooling water
The plant is overcharged
Air or noncondensable gases in the system
A condensing temperature 2°F lower results in 1% additional cooling capacity.
TABLE 2 - EVAPORATING TEMPERATURE TOO LOW
Causes
Fouling in the evaporator
Oil in the evaporator
Insufficient refrigerant charge
An evaporating temperature 2°F higher results in 4% additional cooling capacity.
FRICK
POWERPAC
®
™
MAINTENANCE
OPERATING CONDITIONS
™
Variations in pressures and temperatures within the cooling
cycle can provide information about the operating state of
the chiller package.
Suction and condensing pressures, as well as the tempera-
tures of suction and discharge gas, can provide important
information.
Small changes in the variable pressures and temperatures
are sufficient to create considerable changes in the operat-
ing conditions.
These issues highlight the importance of using the Operat-
ing Log.
TROUBLESHOOTING
An error in the system often leads to changes in operating
conditions, but not to a total shutdown. For that reason,
check the operating state of your PowerPac
intervals.
Refer to compressor manuals for further detail.
If the system does not produce the capacity indicated, check
for possible sources of error. Before taking any action, check
the possible causes indicated in Tables 1 and 2 below.
INCORRECT CAPACITY MEASURING
The PowerPac
control system for control and regulation of the package
capacity according to leaving brine/water temperature. The
Quantum
™
LX has a display to read the operating conditions.
The pressures and temperatures indicated are not exact.
They can only be used to perform approximate capacity
calculations. Exact measurements should be calculated in
accordance with ASHRAE procedures.
Remedies
Adjust water supply or clean the strainer
Clean the condenser
Obtain colder cooling water or reduce compressor capacity
Drain refrigerant into an empty vessel
Remove air from the condenser
Remedies
Clean the evaporator
Inspect the oil return system
Add more refrigerant to the plant.
TROUBLESHOOTING AND
CAPACITY MEASUREMENT
CAPACITY MEASUREMENT
chiller is equipped with a Frick
™
™
at regular
Quantum
LX
™
®
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