Section 6
COMPRESSOR OPERATION
24
CONTROL OR INDICATOR PURPOSE
BLOWDOWN VALVE ASSEMBLY Vents the sump vessel to atmosphere during unload-
ing and shutdown.
THERMAL MIXING VALVE Bypasses fluid flow around the cooler until the former
reaches a temperature of 180
_
F(82
_
C).Useful for fast
warm--up during start. Maintains a minimum tempera-
ture of 180
_
F(82
_
C) during periods of low load or low
ambient temperatures.
FLUID STOP VALVE Blocks the flow of fluid to the compressor during shut-
down, thus preventing the discharge of fluid through
the compressor inlet pipework.
SUMP SIGHT GLASS Indicates level of lubricant in the sump. Located on the
sump side, it should show half--full (compressor
stopped) for proper fluid level.
SEPARATOR RETURN LINE SIGHT GLASSES Indicate fluid flow in the separator return lines. Large
flow should be visible during full load operation; little to
no flow during unloaded operation. Sluggish flow dur-
ing full load operation indicates the need to clean the
strainers fitted to the return lines.
W ATER PRESSURE SWITCH De--energizes the starter, via the Supervisor, if the wa-
ter pressure falls below 10 psig (0.7 bar). This switch is
not adjustable. Used on water--cooled packages only.
DRAIN VALVES Lubricant sump drain valve.
5.3 INITIAL START-UP PROCEDURE
The following procedure should be used to make the
initial start--up of the compressor.
1. Read the preceding pages of this manual thor-
oughly.
2. Jog motor to check for correct rotation of fan (re-
fer to Section 2.6).
3. Be sure that all preparations and checks de-
scribed in the Installation Section have been
made.
4. Open the shut--off valve to the service line.
5. Check for possible leaks in piping.
7. Slowly close the shut--off valve to assure proper
nameplate pressure unload setting is correct.
The compressor will unload at nameplate pres-
sure. If adjustments are necessary, see Control
System Adjustments.
7. Observe the operating temperature. If the operat-
ing temperature exceeds 200
_
F(93
_
C), the
cooling system and installation environment
should be checked.
8. Open shut--off valve to the service line.
9. Reinspect the compressor for temperature and
leaks the following day.
5.4 SUBSEQUENT START- UP PROCEDURE
On subsequent start--ups, check that the proper
level is visible in the fluid sight glass and simply
press the START button. When the compressor is
running, observe the instrument panel and mainte-
nance indicators.
5.5 SHUTDOWN PROCEDURE
To shut the compressor down, simply press the
STOP button.
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