TABLE 4.2
ADJUSTMENT AND
SETTINGS OF SAFETY SWITCHES
SAFETY SWITCH
ADJUSTMENT/SETTING
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PCSTRUCl10N IIAHUA&.JILIHl.0'1NSMUCT10H
Max_ discharge temperature 1)
nonnal setting: 10 K above discharge temperature with package operating under design conditions
max. setting: 93
·c
Max. oil temperature 1)
normal setting: S K above oil temperature
at
oil cooler outfet at selected operaling conditions
max. sening: 65
·c
Max. discharge pressure 1)
nonnaJ setting
:
1 bar above discharge pressure with packag.e operating under design condltlons 2)
max. setting: 21.5 bar
Min. oil/discharge
differentiaf pressure
normal setting: 1.5 bar above discharge pressure
max. setting: 4.0 bar
Min. suction pressure 1)
nonnal setting: f bar below suctfon pressure �ith package operating under design oonditions 2)
min. setting; -0.6 bar
Start control pressure
nonnal setting: 0,5 bar above discharge pressure
max. setting
:
4 bar
Max.
suction pressure
normal setting: depends on built-in volume ratio ot compressor and the refrigerant used. accordîng to
the following table:
refrigerant
built-in 1/0h.sme ratio
2.2
2.6
3.7
4.8
NHs
8.0
ö.2
3.5
2.2
bar(e)
1 bar= 10 N/m = 100kPa = 1.02 kgf/cm"' 14.5 psi
R22
8.7
6.9
4.2
2.8
FOOTNOTES OF T ABLE 4.2
1
)
These
safety switches are provided with a locking device· so that, when cut out, the compressor package does not become operative automat
ically on reb.Jm of the orîginal temperature or pressure. To unlock, an extemal reset button is used but only afler the reason tor cut out has
been lnvestigated_
2
) When setting the max. discharge pressure.safety switch or the min. suction pressure safety switch. it mus1 be cheoked whether ,the dîfference
between áLSCharge pressure and suclion pressure never exceeds the max. allowable value of 20 bar.
+.15 CAPACITY CONTROL ELECTRIC VALVE
ACTUATOR CHECK
With the maîn motor disconnected, the min. oil safety switch
jumpered and the control system energïzed to simulate
operation, the following items should be checked;
a) Run the capacity control valve to the maximum posi
tïon with the manual load switch on the control
cabinet. The capacity indicator on the end of the cam
shaft should read the maximum number of turns of
1he compressor in questîon.
b) Press the manual "load� switch and manually trip the
maximum positiön roller switch. The shaft should ro
tate one full revolution trom the maximum position to
the maximum position stop before the micro switch
stops the motor.
c} lf there are more or less turns of the output shaft, ad
just the maximum position cam as in paragraph s_ 12.
, Return the output shaft to the maximum position trom
the maximum position stop.
e) Mark. the output shaft with a pencil or feit pen.
f) Check the minimum position cam setting by rotating the
capacity control motor counterclockwise trom the maxi
mum position setting with the manual "Unload" switch on
the control panel and counting the number of revolutions
of the marked output shaft. Table 4.3 shows the correct
number of revolutions of the marked output shaft
tor
the
system to
move
the capacity control valve trom the maxi
mum to minimum position. Note the capacity indicator
may or may not read minimum when the number of tums
is correct.
g) lf there are more or less turns of the output shaft, ad
just the minimum position cam as in paragraph 6.12.
h) Again, run the capacity control valve to the maximum
position with the manual "load" switch.
j) With the capacîty control valve at the maximum capacity
position, push the stop button and the capaclty contra!
should move to the minimum position. lf it does not move
to the minimum position, check the unloading wîring cir
cuit.
92.01
Compressor Package GSLP
Pa9e4,7
