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© 2016 Emerson Climate Technologies, Inc.
AE4-1402 R4
lead to compressor overheating. A low pressure cut-out
switch located in the suction line with a cut-out setting
no lower than 20 psig (1.4 bar) is required in all heat
pump applications. For air conditioning units, a cut-out
setting no lower than 55 psig (3.8 bar) will adequately
protect against most low pressure faults. A higher level
of protection for air conditioning units can be realized
if the cut-out setting is increased to 95 psig (6.6 bar) to
prevent evaporator coil icing.
Discharge Temperature Protection
CAUTION
Compressor top cap temperatures can be very
hot. Care must be taken to ensure that wiring or
other materials which could be damaged by these
temperatures do not come into contact with these
potentially hot areas.
The ZPV063 compressors do not have an internal
discharge gas temperature protection. In order for the
variable speed drive to operate properly a thermistor
should be attached to the compressor discharge line
as close as possible and less than 6'' (15cm) from the
compressor discharge fitting. The thermistor is designed
for a 7/8" (22 mm) line and should be properly insulated.
See
Table 6
of
AE-1328
for thermistor temperature vs
resistance values. Refer to
Table 1
for part numbers
of discharge line thermistors.
Figure 7
illustrates the
discharge thermistor.
Motor Overload Protection
The drive will provide motor over current protection in
the event the compressor becomes mechanically locked
or if the load on the compressor motor is abnormally
high. The input power supply to the drive must be
properly fused.
Oil Type
The variable speed scrolls are charged with polyolester
(POE) oil. See the compressor nameplate for the
original oil charge. A complete recharge should be
approximately four fluid ounces (118cc) less than the
nameplate value. Copeland
™
Ultra 32-3MAF, available
from Emerson Wholesalers, should be used if additional
oil is needed in the field. Mobil Arctic EAL22CC,
Emkarate RL22, Emkarate 32CF and Emkarate 3MAF
are acceptable alternatives.
CAUTION! POE oil must be handled carefully and
the proper protective equipment (gloves, eye
protection, etc.) must be used when handling POE
lubricant. POE must not come into contact with any
surface or material that might be harmed by POE,
and spills should be cleaned up quickly with paper
towels, soap and water.
Maximum Tilt Angle
Applications, such as transportation air conditioning or
mobile radar applications, may require the compressor
to operate at some angle from vertical. Service
personnel may be required to maneuver a unit through
a stairwell or other cramped area that might require
tilting the unit. The maximum allowable tilt angles from
horizontal for individual compressors (not tandem or trio
applications) are summarized below:
Max. tilt angle with compressor running = 15°
Max. tilt angle with compressor not running = 60°
Contaminant Control
Copeland Scroll
™
compressors leave the factory with
a miniscule amount of contaminants. Manufacturing
processes have been designed to minimize the
introduction of solid or liquid contaminants. Dehydration
and purge processes ensure minimal moisture levels
in the compressor and continuous auditing of lubricant
moisture levels assure that moisture isn’t inadvertently
introduced into the compressor.
Moisture levels should be maintained below 50 ppm
for optimal performance.
A filter-drier is required
on all R-410A and POE lubricant systems to
prevent solid particulate contamination, oil
dielectric strength degradation, ice formation, oil
hydrolysis, and metal corrosion.
It is the system
designer’s responsibility to make sure the filter-drier is
adequately sized to accommodate the contaminants
from system manufacturing processes that leave
solid or liquid contaminants in the evaporator coil,
condenser coil, and interconnecting tubing plus any
contaminants introduced during the field installation
process. Molecular sieve and activated alumina are
two filter-drier materials designed to remove moisture
and mitigate acid formation. A 100% molecular sieve
filter can be used for maximum moisture capacity. A
more conservative mix, such as 75% molecular sieve
and 25% activated alumina, should be used for service
applications.
Refrigerant Piping
Particular attention must be given to the system
refrigerant pipe size with the variable speed scrolls.
ASHRAE guidelines for pipe sizing should be followed
