Bryant R-22 - Manual (Page 28)

5. Scratch matching marks on stubs in old compressor. Make
corresponding marks on replacement compressor.
6. Use torch to remove stubs from old compressor and to
reinstall them in replacement compressor.
7. Use copper couplings to tie compressor back into system.
8. Evacuate system, recharge, and check for normal system
operation.
9. Copeland CR-6 and scroll compressors have copper-plated,
steel-suction ports. Excess heat during brazing will burn off
copper plating. See Brazing section for additional informa-
tion.
COPELAND SCROLL COMPRESSOR
I. FEATURES
The scroll compressor pumps refrigerant through the system by the
interaction of a stationary and an orbiting scroll. (See Fig. 29.) The
scroll compressor has no dynamic suction or discharge valves, and
it is more tolerant of stresses caused by debris, liquid slugging, and
flooded starts. Due to the design of the scroll compressor, the
internal compression components unload (equalize pressure) on
shutdown. The white oil (Sontex 200LT) used in the scroll is
compatible with 3GS oil, which can be used if additional oil is
required. (See Table 13 for oil recharge requirements.)
II. TROUBLESHOOTING
Troubleshooting mechanical or electrical problems in a scroll
compressor is the same as for a reciprocating compressor, except
that a scroll compressor should never be allowed to pump into a
vacuum. If a pumpdown procedure is used, the scroll compressor
is capable of pumping into a vacuum very quickly, which could
cause fusite arcing and compressor failure. See Step IV of
Reciprocating Compressor section for removal and replacement.
III. DISCHARGE THERMOSTAT
Some scroll compressors have a discharge thermostat that recip-
rocating compressors do not have. This thermostat is mounted in a
well in the top of the compressor shell to sense if the discharge
temperature reaches 290°F and shuts down the compressor to
prevent damage to it. When the temperature of the thermostat
reaches 140°F, power is restored to the compressor.
To determine if the thermostat is operating properly, either attach
the thermocouple of an electronic thermometer to the dome of the
compressor near the thermostat, or remove the thermostat and
place the thermocouple inside the well. The electronic thermom-
eter must be capable of reading at least 300°F. Start the unit and let
it run for at least 15 minutes to obtain normal operating conditions.
Watch the thermometer to see if it is approaching 270°F. If the
thermocouple is located on the dome near the discharge thermo-
stat, there could be a 20° difference between well and dome
temperatures. If the temperature approaches 270°F, repair system
problem, such as low charge, blocked condenser coil, and so forth.
If the temperature does not approach 270°F, replace discharge
thermostat.
Replacing Discharge Thermostat
To replace the discharge thermostat, refer to the Installation
Instructions packaged with the replacement discharge thermostat
kit. (See Fig. 30.)
IV. DISCHARGE SOLENOID VALVE
Some larger units equipped with scroll compressors contain a
solenoid valve that is piped between the discharge tube and suction
tube of the compressor. The purpose of the solenoid valve is to
TABLE 13—COMPRESSOR OIL RECHARGE
COMPRESSOR MODEL
RECHARGE
(FL. OZ.)
OIL TYPE
Carlyle/Scroll
″
J
″
Type 44 Suniso 3GS
SC, SRD450AC 34
Zerol 150
w/3 percent
Syn-O-Ad
SR 52
SRH482, SRY482 68
SRH602, SRY602 70
Copeland
CRG3, CRH3, CRJ3, CRK3, CRL3 51
Suniso 3GS
CRN5, CRP5, CRT5, CTH1, CTL1 66
CRC4, CRZ4 36
CR16K6 THROUGH CR42K6 42
*ZR18K1 19
*ZR23K1, ZR28K1 24
*ZR34K1 30
*ZR40K1 34
*ZR49K1-PFV 56
*ZR49K2-TF5, ZR49K2-TFD 56
*ZR61K2-PFV 56
*ZR61K2-TF5, ZR61K2-TFD 66
Tecumseh
AV55 50
Suniso 3GS AW55 30
AG 60
Bristol
H23A 52
Suniso 3GS
H23B 37
H24A3, H24A4 47
H24A5 52
H25A, H26A 62
H25B, H26B, H29B 32
*Copeland scrolls are charged initially with Sontex 200LT white oil. Since this
oil is not commercially available, use 3GS.
Fig. 29—Scroll Compressor Refrigerant Flow
A90198
Scroll Gas Flow
Compression in the scroll is
created by the interaction of
an orbiting spiral and a
stationary spiral. Gas enters
an outer opening as one of the
spirals orbits.
The open passage is sealed off
as gas is drawn into the spiral.
By the time the gas arrives at
the center port, discharge
pressure has been reached. Actually, during operation, all
six gas passages are in various
stages of compression at all
times, resulting in nearly con-
tinuous suction and discharge.
As the spiral continues to orbit,
the gas is compressed into an
increasingly smaller pocket.
1
2 3
5 4
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