Accumulators; Mufflers - Emerson Copeland Scroll ZRH49KJE Application Manuallines

3.4

Accumulators

CAUTION
Inadequate lubrication! Bearing destruction! Minimise liquid refrigerant
returning to the compressor. Too much refrigerant dilutes the oil. Liquid
refrigerant can wash the oil off the bearings leading to overheating and
bearing failure.
CAUTION
Screen blocking! Compressor breakdown! Use screens with at least 0.6
mm openings (30 x 30 meshes per inch). Screens with a finer mesh can
easily become plugged causing oil starvation to the compressor bearings. A
compressor breakdown may be the consequence.
Irrespective of system charge, oil dilution may occur when large amounts of liquid refrigerant
repeatedly flood back to the compressor during:
normal off cycles
defrost
varying loads
To determine if an accumulator is required, refer to Technical Information "Excessive Liquid
Floodback Tests".
If an accumulator must be used, an oil return orifice size in the range of 1.4 mm in diameter is
recommended.
If an accumulator is used it is recommended that it be sized to hold from 50% to 70% of the
system charge.
If an accumulator is fitted, and there is no crankcase heater, it should be piped to allow free
liquid drainage during the off cycle.
A large area protective screen no finer than 30 x 30 mesh (0.6 mm openings) is required to
protect this small orifice from plugging with system debris.
ANW.4.05.00
SCROLL
Figure 6: Suction accumulator installation
Tests have shown that a small screen with a fine mesh can easily become plugged causing oil
starvation to the compressor bearings. Such blockage can result in compressor failure.
3.5

Mufflers

External mufflers, normally applied to piston compressors in the past, may not be required for
TM
Copeland Scroll compressors.
Individual system tests should be performed to verify acceptability of sound performance. If
adequate attenuation is not achieved, use a muffler with a larger cross-sectional area to inlet
area ratio. A ratio of 20:1 to 30:1 is recommended.
A hollow shell muffler will work quite well. Locate the muffler at minimum 15 to maximum 45 cm
from the compressor for the most effective operation. The farther the muffler is placed from the
compressor within these ranges, the more effective it is. Choose a muffler with a length of 4 to
10-15 cm.
C6.2.7/0302-1007/E 7