IM 1044-2
Centrifugal Chillers
55
Maintenance Schedule, Cont.
Maintenance Check List Item
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IV. Condenser
A. Evaluation of Temp Approach (NOTE 2)
O
B. Test Water Quality
V
C. Clean Condenser Tubes (NOTE 2)
X
X
D. Eddy current Test - Tube Wall Thickness
V
E. Seasonal Protection
X
V. Evaporator
A. Evaluation of Temp Approach (NOTE 2)
O
B. Test Water Quality
V
C. Clean Evaporator Tubes (NOTE 3)
X
D. Eddy current Test - Tube Wall thickness
V
X
E. Seasonal Protection
X
VI. Expansion Valves
A. Operational Evaluation (Superheat Control)
X
VII. Starter(s)
A. Examine Contactors (hardware and operation)
X
B. Verify Overload Setting and Trip
X
C. Test Electrical Connections (Infrared temp measurement)
X
VIII. Optional Controls
A. Hot Gas Bypass (verify operation)
X
KEY:
O
= Performed by in-house personnel.
X
= Performed by
Daikin
authorized service personnel. (NOTE 4)
V
= Normally performed by third parties.
NOTES:
1.
Some compressors use power factory correction capacitors and all have a surge capacitor (excepting units with solid state
starters). The surge capacitor can be installed out of sight in the compressor motor terminal box. In all cases, capacitors
must be disconnected from the circuit to obtain a useful Megger reading. Failure to do so will produce a low reading. In
handling electrical components, only fully qualified technicians must attempt service.
2.
Approach temperature (the difference between the leaving water temperature and the saturated refrigerant temperature) of
either the condenser or evaporator is a good indication of tube fouling, particularly in the condenser, where constant
flow usually prevails.
Daikin's
high efficiency heat exchangers have very low design approach temperatures, in the order
of one to one and one half degrees F.
The chiller unit controller can display the water and the saturated refrigerant temperatures. Simple subtraction will give
the approach. It is recommended that benchmark readings (including condenser pressure drop to confirm future flow
rates) be taken during startup and then periodically afterward. An approach increase of two-degrees or more would
indicate that excessive tube fouling could be present. Higher than normal discharge pressure and motor current are also
good indicators
3.
Evaporators in closed fluid circuits with treated water or anti-freeze are not normally subject to fouling, hover it is
prudent to check the approach periodically. Some evaporators may have a mixture of ¾-inch and 1-inch tubes.
4.
Performed when contracted for, not part of standard initial warranty service.
5.
Oil filter change and compressor teardown and inspection should be done based on the results of the annual oil test
performed by a company specializing in this type of test. Consult
Daikin
Service for recommendations.
