Carlyle 06ZCE1H3AA06013, Инструкция по применению

Страница: 11 / 24

11
MEDIUM/HIGH TEMPERATURE SYSTEM OIL
MANAGEMENT (R-134a, R-1234ze)
Oil Pressure Requirements
System pressure is used to generate the oil pressure required to lu-
bricate bearings and provide the oil that acts as a seal between the
screw rotors and the bores. Oil flow and level is monitored con-
tinuously during compressor operation.
The oil pressure must meet the following criteria, based on
P
DIS-
CHARGE
, P
SUCTION
, and P
OIL
, as shown in Fig. 7:
1. P
OIL
> [0.7 x ( P
DISCHARGE
– P
SUCTION
) +
P
SUCTION
]
2. P
OIL
> [ P
SUCTION
+ 1.0 bar] 75 seconds after start
The unit control system must monitor the oil pressure differential,
as well as the operating condition, so the compressor can be shut
down if the minimum requirements are not met for any duration
exceeding 15 seconds.
This time delay has two functions: first, to avoid nuisance tripping
during normal and transient operation, and second, to allow the
system sufficient time to develop pressure differential during
start-up.
The compressor must be shut down and prevented from restarting
when the low oil pressure safety is tripped. The safety should be a
manual reset type that locks out compressor operation until the
system is serviced.
Carlyle offers a Compressor Protection Module package to pro-
vide protection against loss of oil flow, oil level, and elevated dis-
charge gas temperature.
Oil Separator Recommendations
The 06Z VFD compressor requires an oil separator. The com-
bined oil capacity of the oil separator sump, the oil reservoir, and
the oil cooler, should be greater than the values shown in Table 4.
The separator should be selected to provide a maximum oil carry-
over leaving the separator required by that system/application.
Approximate oil flow versus compressor pressure differential
(Discharge Pressure - Suction Pressure) is shown in Fig. 7. Addi-
tional oil charge may be required for systems that have longer tub-
ing sets.
Fig. 7 — Oil Supply at Compressor
Oil Heater Recommendations for Air-Cooled
Models
For the typical oil separators used with the a 500-watt flexible
strip heater is recommended. The heater should be wired to oper-
ate when the compressor is OFF. This minimizes the migration of
refrigerant to the oil stored in the sump. Figure 6 shows the mini-
mum oil temperatures that must be maintained when the compres-
sor is not operating based on the outdoor ambient temperature
(OAT). If the application will allow refrigerant to collect in the
compressor, then a heater must be installed on the compressor.
Running unit water that is at least 20°F (11°C) below OAT, if pos-
sible, can be used to prevent refrigerant from collecting in the
compressor. Carlyle recommends that the oil temperature be mon-
itored in warm climate applications and that the oil separator heat-
er be cycled off if oil temperatures reach 190°F (88°C).
Oil Level Safety Switch
An oil level safety switch must be installed in the sump of the oil
separator or the oil reservoir, depending on the system design.
Carlyle recommends an oil level safety switch that interrupts
compressor operation if oil levels are below adequate levels.
Enough oil should remain in the sump when the switch is opened
for the compressor to operate for at least one minute before com-
pletely running out of oil.
Oil Filter
Provisions should be made to isolate the oil filter using some
combination of shutoff valves and/or check valves, see Fig. 8.
This will allow for the filter element to be replaced without remov-
ing or isolating the charge in the unit.
Because of the long bearing life requirements, filtration for this
compressor is very stringent. The Beta Ratio for this filter is
greater than or equal to 200 for a five micron particle size evaluat-
ed using ISO 16889 (

(5)

200).
Filter areas must also be sufficient to avoid premature clogging of
the filter during normal operation. An alarm in the controls should
be signaled any time the pressure drop across the filter ( P
DIS-
CHARGE
– P
OIL
) exceeds 40 psid, indicating the filter needs to be
replaced.
Table 4 — Oil Capacity
COMPRESSOR
MODEL
OIL
SEPARATOR
PART
NUMBER
TYPE
INLET
DIAMETER
(IN.)
OIL
CHARGE
(GPM)
06ZC 30XV50059401 Vertical 3.125 7
06ZF 30XV50122601 Vertical 4.125 7
06ZJ 30XV80004301 Horizontal 4.500 8
LEGEND
A/C — Air-Cooled