Special Handling Consideration For Zb58-Zb114; Crankcase Heaters Requirement; System Protection Guidelines - Emerson ZB Copeland Scroll Product Manual

ZB
Series
Application Guide

3.8 Special handling consideration for ZB58-ZB114

ZB58- ZB114 model compressors have the suction fitting located low on
the shell. Due to this, its recommended to leave the suction connection
plug in place until the compressor is set into the unit. The discharge
connection plug should be removed first before pulling the suction
connection plug to allow the dry air pressure inside the compressor to
escape. Pulling the plugs in this sequence prevents oil mist from coating
the suction tube making the brazing difficult.. The copper coated steel
suction tube should be cleaned before brazing. No object (example a
swaging tool) should be inserted deeper than 50mm into the suction
tube or it might damage the suction screen and motor.

4. System Protection Guidelines

4.1 Accumulator Requirement:
Due to the scrolls' inherent ability to handle liquid refrigerant in flooded
start and defrost cycle operation conditions, accumulators may not be
required. An accumulator is required on single compressor systems when
the charge limitations exceed those values listed in Table 2. On systems
with defrost schemes or transient operations that allow prolonged
uncontrolled liquid return to the compressor, an accumulator is required.
Excessive liquid flood back or repeated flooded starts will dilute the oil
in the compressor causing inadequate lubrication and bearing wear.
Proper system design will minimize liquid flood back, thereby ensuring
maximum compressor life.
Table 2
Charge Limitations
Models Charge Limits
ZB15- ZB48 4.5 Kgs
ZB58-ZB114 7 Kgs

4.2 Crankcase Heaters Requirement

Single-phase models
No crankcase heaters are required on single-phase scroll compressors.
Three-phase models
ZB15–ZB48- outdoor only
Crankcase heaters are required on three phase compressors where the
system charge exceeds 4.5 Kgs. Table 3 lists the specification of applicable
crankcase heaters.
ZB58-ZB114
Crankcase heaters are required where the system charge exceeds 7
Kgs. The crankcase heater must be located below the suction inlet.
Table 3 lists the specification of applicable crankcase heaters
Table 3
Crankcase Heater
Model Part No
ZB15-ZB48 018-0072-04
ZB58-ZB114 018-0067-01
The listed crankcase heaters are intended for use only when there is limited
access (Table 3). The heaters are not equipped for use with electrical
conduit. Where applicable, electrical safety codes require lead protection,
a crankcase heater terminal box should be used. Recommended
crankcase heater terminal box and cover part kit numbers are available
with Copeland Application Engineering Department.
The crankcase heater must remain energized during the compressor off cycles.
The initial start in the field is a very critical period for any compressor
because all load bearing surfaces are new and require a short break-in
period to carry high loads under adverse conditions. The crankcase
heater must be turned on a minimum of 12 hours prior to starting
the compressor. This will prevent oil dilution and bearing stress on initial
start up. If it is not feasible to turn on the crankcase heater 12 hours in
advance of starting the compressor, then use one of the techniques listed
below to prevent possible flooded start damage to the compressor: 1)
Direct a 500 watt heat lamp or other safe heat source at the lower shell
of the compressor for approximately 30 minutes to boil off any liquid
refrigerant prior to starting; or 2) Bump start the compressor by manually
energizing the compressor contactor for about one second. Wait five
seconds and again manually energize compressor for one second. Repeat
this cycle several times until the liquid in the shell has been boiled off and
the compressor can be safely started and run continuously.
10
Volts Watts Length
240 70 48" (122 mm)
240 90 48" (122 mm)