Compressor Interconnection - Carlyle 06D Series Application Manual

1.9 Compressor Interconnection

All 06D and 06E compressors are suitable for interconnec-
tion on common refrigerant circuits. General suction and
discharge line piping recommendations are shown in
Figures 1 and 2, respectively. For a complete guide to sys-
tem piping practices, the Carrier System Design Manual
(Part 3 Piping Design) is again recommended.
When only two 06D or 06E compressors of the same size
are to be connected in parallel, the oil equalization can
be accomplished with a single oil equalization line. This
line can equalize both oil and gas. This method of equal-
ization is only recommended when there are two com-
pressors of the same size and the oil equalization line is
short (2 to 4 feet, .6 to 1.2 meters long). In this case, a
single 1-1/8" line can be used. Since this line equalizes
both oil and gas, it is important that it be level to permit
the lower half as an oil equalizer and the upper half as a
gas equalizer.
The 06E compressors have two sightglass connections,
either of which may be removed for installation of the
equalizer line. A small oil equalization check valve must
also be added to those 06E compressors used in paral-
lel. This check valve is part of the 06EA900101 compres-
sor interconnection package and must be installed in the
rotor locking bolt (torqued to 13-16 lb-ft, 1.8-2.2 kg-m)
of each compressor (see Figure 3). The 06E rotor bolt is
accessible by removing the suction strainer from the
motor end cover. Installation of the check valve is best
accomplished just prior to mounting the suction service
valve.
Suction Line
Compressor Compressor
1 2
RECOMMENDED
Compressor Compressor
1 2
RECOMMENDED
Figure 1 – Suction Piping
Compressor Compressor
1 2
NOT RECOMMENDED
Excessive Liquid Refrigerant Foodback
will be Predominantly in Comp No. 2
Compressor Compressor
1 2
Cycles Continuously
1
RECOMMENDED
Cycles
Most Often
1
Figure 2 – Discharge Piping
Figure 3 – Rotor Locking Bolt
The 06D compressors have only one sightglass and pro-
vision must be made for a sightglass in the oil equalizer
line when the 06D compressors are interconnected
using an oil equalization line. The 06D oil equalizer
interconnection package is 06DA900092. The 06D com-
pressors do not utilize or require the check valve in the
rotor lock bolt.
When more than two compressors are to be connected
in parallel or if 06D/E compressors of different displace-
ments are to be connected in parallel, an oil control sys-
tem utilizing an oil separator, oil reservoir, and floats is
recommended. Several manufacturers supply this type of
oil management system. It is important that floats are
properly selected for Carlyle's 06D and 06E compres-
sors. For the 06D compressor, a special adapter is
12
Run
2 1
Dead-heading
NOT RECOMMENDED
2 3
RECOMMENDED
2
Run
Continuously
4