Emerson ZB Copeland Scroll Service Manual download pdf (Page 9)

ZB Series

Application guide

Crankcase heater

Single-phase scroll compressor does not require installation of

a crankcase heater.

When the refrigerant charge exceeds the values listed in the

following table, or, when the refrigerant is charged at-site, a

crankcase heater is necessary for the three-phase compressor.

Compressor Models Refrigerant Charge(kg)

ZB15-ZB45 4.5

ZB50-ZB88 7.2

ZB92-ZB11M 7.7

Pressure controller

To ensure the safe operation of the refrigeration system, Emerson

suggests that all systems be equipped with high- and low-pressure

switches.

See the following table for the recommended setting values (unit:

bar, gauge pressure).

Control type R22 R404A/507 R134a

High pressure (maximum) 26 30 18

Low pressure (minimum) 1.7 1.15 0.3

Gas-liquid separator

Copeland scroll compressor has a greater capacity to resist liquid because

of some inherent characteristics. It is possible that the gas-liquid

separator does not need to be used in most of the systems. However, it is

suggested that the gas-liquid separator be used when:

a large quantity of the liquid refrigerant in the system returns

continuously into the compressor within a period of regular stop

there is defrosting

there is a variable load regardless of the charged quantity of refrigerant

in the system

it is impossible to control the liquid-return phenomenon or wet start

because of the dilution of lubricating oil

If the gas-liquid separator is used in the system, it is suggested that the

dimension of the return oil orifice should be within 1-1.9mm. Also, the

filtering area of the protecting screen should be large enough, and its

mesh size not below 30x30 (diameter of 0.6mm). It is not advisable to use

screen finer than 30x30 mesh in the system anywhere in order to protect

the orifice from being blocked by debris.

Drying filter and humidity indicator

The filter drier installed in the liquid piping should be large enough and

adequate for uninterrupted operation. The dehumidifier should be

selected according to the flow rate of the refrigerant. Do not use

dehumidifiers that can turn into liquid state after absorbing a large

quantity of wet steam, such as potassium chloride. It is suggested that

porous block dehumidifiers are used to absorb the wet steam or acid and

prevent metal fragments from invading. The filter drier should be

installed after a second vacuum operation has been carried out. The sight

glass for the humidity indicator should be installed in a clearly visible

position on the liquid piping, in order to facilitate the checking of

refrigerant flow rate.

Installation of the crankcase heater

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Emerson ZB Copeland Scroll Service Manual Page 9

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