KeepRite K40-CU-IM-13 Installation And Maintenance Instructions Manual - page 29
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System Operational Check List
When the system has been running trouble free for an extended time (two weeks or more) and design
conditions are satisfied, the following check list should be followed:
(1)
Check that compressor discharge and suction pressures are operating within the allowable design
limits for the compressor. If not, take the necessary corrective action.
(2)
Check the liquid line sight glass and expansion valve operation. If there is an indication that the system
is low on refrigerant, thoroughly check the system for leaks before adding refrigerant.
(3) Check
the
level of the oil in the compressor sight glass (if so equipped). Add oil as necessary.
(4)
The thermostatic expansion valve must be checked for proper superheat settings. The sensing bulb
must have positive contact with the suction line and should be insulated. Valves operating at a high
superheat setting results in low refrigeration capacity. Low superheat settings can cause liquid slugging
and compressor bearing washout. (Refer to the section on compressor and evaporator superheats)
(5) Check
the
voltage and amperage readings at the compressor terminals. Voltage reading must be
within the recommended guidelines. Normal operating amperages can be much lower than the
compressor nameplate values.
(6)
To check the high pressure control setting it is necessary to build up the head pressure to the cut-out
point of the control. This can be done by stopping the condenser fan(s) (air cooled condensing units) or
pump and watching the pressure rise on a high pressure gauge to make sure the high pressure control
is operating at the setting.
(7) Check
the
low pressure settings by throttling the compressor shut-off valve and allowing the
compressor to pump down. This operation must be done with extreme caution to avoid too sudden a
reduction in crankcase pressure, which will cause oil slugging and possible damage to the compressor
valves. Close the valve a turn at a time while watching the compound gauge for change and allowing
time for the crankcase pressure to equalize with the pressure control bellows pressure. The slower the
pressure is reduced, the more accurate will be the check on the pressure control setting.
(8) Recheck
all
safety and operating controls for proper operation and adjust as necessary.
(9) Check
defrost controls for initiation and termination settings, and the length of defrost period. Set
the fail safe on the time clock at the length of defrost plus 25 %.
(10)
If the system is equipped with winter head pressure controls (fan cycling or flooded valves), check for
operation.
(11)
Fill in the Service Log in the back of this Installation Manual.