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14 MAINTENANCE
Maintenance operations are fundamental in order to keep the units running properly, from both a purely functional and an
energetic points of view.
Every unit comes with a logbook, in which the user or the person delegated to machine maintenance can keep all the
required notes, in order to keep a historical log.
A lack of notes in the logbook could be considered proof of careless maintenance.
14.1 GENERAL
IMPORTANT!
Beyond the cadences of checks recommended in the following, in order to keep the unit at optimum levels of performance
and efficiency and prevent incipient failures, we recommend periodic visits of inspection and control of the unit by qualified
personnel.
In particular, we recommend:
4 annual visits to units that operate about 365 days / year (quarterly)
2 visits per year for units with seasonal operation about 180 days / year (one at the start of the season and another one at
mid-season)
1 annual visit for units with seasonal operation of about 90 days / year (starting seasonal)
It's important that during the initial start-up and periodically during operation routine checks are carried out. Among them
you must also check the suction and condensation as well as the sight glass located on the liquid line.
Check through the microprocessor installed on the unit if the unit is working within normal parameters of superheating and
subcooling. A routine maintenance program recommended is shown at the end of this chapter while a card collection of
operating data is at the end of this manual. It is suggested to record on a weekly basis all the operating parameters of the
unit. The collection of these data will be very useful to technicians, in case technical assistance is requested
Compressor Maintenance IMPORTANT!
This inspection must be performed by qualified and trained personnel.
The analysis of vibration is a great tool for checking the mechanical conditions of the compressor.
It is recommended to check the value of the vibration immediately after starting and periodically on an annual basis.
Compressor Electrical Connections
It is very important that all the compressors are wired correctly for proper rotation. These compressors will not tolerate
reverse rotation. Verify correct rotation/phasing using a rotation meter.
If wired incorrectly the compressor will make excessive noise, will not pump and will draw about half the normal current. It
will also become very hot if allowed to run for an extended period.
NOTICE: Do not "bump" the compressor to check rotation as incorrect rotation could cause compressor motor
failure in as little as 4 to 5 seconds!
Improper rotation of the compressors is indicated by a compressor module trip, noisy operation, no pressure difference on
manifold gauges and low amp draw.
Compressor Replacement
If the chiller suffers a failed compressor, use these steps for replacement:
Each compressor has lifting eyes. Both lifting eyes must be used to lift the failed compressor.
After a mechanical failure of a compressor, it is necessary to change the oil in the remaining compressor and also replace
the liquid line filter drier. After an electrical failure of a compressor, it will also be necessary to change the oil in the
remaining compressor, replace the filters driers and add a suction filter drier with clean-up cores.
Make sure that a heater is correctly installed on the compressor. The heater helps prevent dry starts.
Note: Do not alter the refrigerant piping in any way as this can affect compressor lubrication.
Refrigerant System Open Time
Units use oil and therefore refrigerant system open time must be kept to a minimum. The following procedure is
recommended:
Leave a new compressor sealed until it is ready to be installed in the unit. Maximum system open time is dependent upon
ambient conditions, but do not exceed one hour open time.
Plug the open refrigerant line to minimize moisture absorption. Always change the liquid line filter drier.
Do not leave oil containers open to the atmosphere. Always keep them sealed.
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