Installation, Operation and Maintenance 8 - 1
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Overview
This section describes preventive maintenance
procedures and intervals for the Series R unit. Use a
periodic maintenance program to ensure maximum
performance and efficiency of the Series R units.
An important aspect of the chiller maintenance
program is the regular completion of the “Series R
Operating Log”; an example of this log is provided in
this manual. When filled out properly the completed
logs can be reviewed to identify any developing
trends in the chiller's operating conditions.
For example, if the machine operator notices a
gradual increase in condensing pressure during a
month's time, he can systematically check--then
correct--the possible cause(s) of this condition (e.g.,
fouled condenser tubes, non-condensables in the
system).
Weekly Maintenance and Checks
After the unit has operated for approximately 30
minutes and the system has stabilized, check the
operating conditions and complete the procedures
below:
q Log the chiller.
q Check evaporator and condenser pressures with
gauges and compare to the reading on the Clear
Language Display. Pressure readings should fall
within the following ranges specified in the
Operating Conditions table:
NOTE: Optimum condenser pressure is dependent
on condenser water temperature, and should equal
the saturation pressure of the refrigerant at a
temperature 2 to 5
°
F above that of leaving condenser
water at full load.
M o n t h l y M a i nt e n a n c e a n d C h e c k s
q Review operating log.
q Clean all water strainers in both the chilled and
condensing water piping systems.
q Measure the oil filter pressure drop. Replace oil
filter if required. Refer to “Service Procedures”.
q Measure and log the subcooling and superheat.
Refer to
Table 26
q If operating conditions indicate a refrigerant
shortage, leak check the unit using soap bubbles.
q Repair all leaks.
q Trim refrigerant charge until the unit operates in
the conditions listed in
Table 26
at full load, ARI
conditions.
NOTE: ARI conditions are: condenser water: 85
°
F
and 3 GPM/XXX tons and evaporator water: 54-44
°
F
Table 26
Operating Conditions at Full Load
q If full load conditions can not be met, use
Table 27
, to trim the refrigerant charge
NOTE: Conditions at minimum must be: entering
condenser water: 85
°
F and entering evaporator
water: 55
°
F
Table 27
Operating Conditions at Minimum Load
NOTE: * 1.0
°
F for new unit.
Description Condition
Evaporator pressure 40-55 psig
Condensing pressure 85-120 psig
Discharge superheat 17
°
F
Subcooling 5-10
°
F
EXV percent open 40-50% open in Auto mode
NOTE: All conditions stated above are based on
the unit running fully loaded, running at ARI
conditions.
Description Condition
Evaporator approach *less than 7
°
F (non-glycol
applications)
Condensing approach *less than 7
°
F
Subcooling 2-3
°
F
EXV percent open 10-20 % open
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