Technical data
3
AE-1318 R1
© 2008 Emerson Climate Technologies
Printed in the U.S.A.
Application Engineering
BULLETIN
suction header of suffi cient volume to prevent liquid
migration to the compressors is used. Excessive liquid
fl oodback or repeated fl ooded starts will dilute the oil
in the compressor causing inadequate lubrication and
bearing wear. Proper system design will minimize liquid
fl oodback, thereby ensuring maximum compressor life.
If an accumulator must be used, an oil return orifi ce
size in the range of 0.040 - 0.075 inches (1 - 1.9 mm)
is recommended. A large-area protective screen no
fi ner than 30 x 30 mesh (0.6 mm openings) is required
to protect this small orifi ce from plugging with system
debris. Tests have shown that a small screen with
a fi ne mesh can easily become plugged causing oil
starvation to the compressor bearings.
Screens
The use of screens fi ner than 30 x 30 mesh (0.6 mm
openings) anywhere in the system is not recommended.
Field experience has shown that fi ner mesh screens
used to protect thermal expansion valves, capillary
tubes, or accumulators can become temporarily or
permanently plugged with normal system debris
and block the fl ow of either oil or refrigerant to the
compressor. Such blockage can result in compressor
failure.
Crankcase Heater
Crankcase heaters are required on systems when the
system charge exceeds the recommended charge
limit. See Table 2.
The listed crankcase heaters (Table 3) are intended
for use only when there is limited access. The heaters
are not equipped for use with electrical conduit. Where
applicable, electric safety codes require heater lead
protection, a crankcase heater terminal box should
be used. Recommended crankcase heater terminal
cover and box numbers are listed in Table 3A. If
there are any questions concerning the application,
contact the Emerson Climate Technologies Application
Engineering department.
Advanced Scroll Temperature Protection (ASTP)
After extensive research and trials Emerson Climate
Technologies found a way to install a Therm-O-
Disc® temperature sensitive snap disc in the ZB50,
ZB58, ZB66, ZB76, ZB95, ZB88 and ZB114 scroll
compressors. This acts to protect the compressor from
Figure 2
TABLE 3
CRANKCASE HEATERS
Model Part No. Volts Watts Leads
ZB50, ZB58,
ZB66, ZB76
ZB88, ZB95
ZB114
Select by voltage
018-0067-00
018-0067-01
018-0067-02
018-0067-03
120
240
480
575
90
90
90
90
48"
48"
48"
48"
Select by voltage and lead length
ZB56
ZB68
ZB75
ZB92
ZB11M
018-0077-00
018-0077-01
018-0077-02
018-0077-03
018-0077-04
018-0077-05
018-0077-06
240
120
480
575
240
480
575
70
70
70
70
70
70
70
26"
26"
26"
26"
34"
34"
34"
TABLE 3A
CONDUIT READY HEATER BOX KITS
Model Number Kit Number
ZB50, ZB58, ZB66
ZB76, ZB88, ZB95, ZB114
998-7029-00
ZB56, ZB68, ZB75
ZB92, ZB11M
998-7015-00