Air Conditioning (A/C) System Performance Test. Saturn L200/LW200 2003

For 1990-2009 cars only

Makes 🢒 Saturn 🢒 2003 🢒 L200/LW200 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Air Conditioning (A/C) System Performance Test

Table 1:	System Condition Charts - Definition and Usage
Table 2:	Normal System Performance Service Stall - L61
Table 3:	Normal System Performance 72 Km/h (45 mph) - L61
Table 4:	Normal System Performance Service Stall High Humidity - L61
Table 5:	General System Condition - Low Refrigerant Charge - L61
Table 6:	General System Condition Refrigerant/Oil Overcharge - L61
Table 7:	Specific System Condition-Compressor No-Pump - L61
Table 8:	Specific System Condition - Compressor at Minimum Displacement - L61
Table 9:	Specific System Condition - Compressor at Maximum Displacement - L61
Table 10:	Specific System Condition - TXV Restricted - L61
Table 11:	Specific System Condition - TXV Open - L61
Table 12:	General System Condition - TXV Closed - L61
Table 13:	General System Condition - High or Low Side Restrictions - L61
Table 14:	Normal System Performance Service Stall - L81
Table 15:	Normal System Performance 72 Km/h (45 mph) - L81
Table 16:	Normal System Performance Service Stall High Humidity - L81
Table 17:	General System Condition - Low Refrigerant Charge - L81
Table 18:	General System Condition Refrigerant/Oil Overcharge - L81
Table 19:	Specific System Condition-Compressor No-Pump - L81
Table 20:	Specific System Condition - Compressor at Minimum Displacement - L81
Table 21:	Specific System Condition - Compressor at Maximum Displacement - L81
Table 22:	Specific System Condition - TXV Restricted - L81
Table 23:	Specific System Condition - TXV Open - L81
Table 24:	General System Condition - TXV Closed - L81
Table 25:	General System Condition - High or Low Side Restrictions - L81

System Condition Charts - Definition and Usage

Degrees*	Suction*	Discharge*	Outlet*
21°C (70°F)	200-213 kPa (29-31 psi)	723-916 kPa (105-133 psi)	5-8°C (41-46°F)
27°C (80°F)	193-207 kPa (28-31 psi)	999-1102 kPa (145-160 psi)	6-7°C (42-45°F)
33°C (90°F)	186-200 kPa (27-29 psi)	1275-1791 kPa (185-260 psi)	7-8°C (45-47°F)
38°C (100°F)	179-193 kPa (26-28 psi)	1550-2136 kPa (225-310 psi)	8-9°C (46-48°F)
Important: Statements contain additional information to help you confirm your diagnosis and lead you to a corrective action. When ALL pressure and temperature readings fall within the ranges of a given chart, use that chart to repair the vehicle. Key: Statements are used to interpret the pressure and temperature readings compared to normal system performance. If testing above or below ambient temperatures listed, rely on key statements to diagnose system. Degrees - If the ambient air temperature is Suction - and the low side gage should read Discharge - and the high side gage should read Outlet - and the right center air temperature should be

Normal System Performance Service Stall - L61

Degrees*	Suction*	Discharge*	Outlet*
21°C (70°F)	200-213 kPa (29-31 psi)	723-916 kPa (105-133 psi)	5-8°C (41-46°F)
27°C (80°F)	193-207 kPa (28-30 psi)	999-1102 kPa (145-160 psi)	6-7°C (42-45°F)
33°C (90°F)	186-200 kPa (27-29 psi)	1275-1791 kPa (185-260 psi)	7-8°C (45-47°F)
38°C (100°F)	179-193 kPa (26-28 psi)	1550-2136 kPa (225-310 psi)	8-9°C (46-48°F)
Degrees - If the ambient air temperature is Suction - and the low side gage should read Discharge - and the high side gage should read Outlet - and the right center air temperature should be

Important: To ensure accurate pressure and temperature readings make sure the vehicle is properly set up to run the performance test. Refer to vehicle set up section in this manual. ALL TEST PARAMETERS MUST BE FOLLOWED TO OBTAIN ACCURATE READINGS. Confirm system performance by touching the suction and discharge pipes at the compressor. The suction pipe will be cold and the discharge pipe will be hot.

Important: Use a refrigerant identifier to verify refrigerant purity. Non-condensable gases or refrigerant substitutes will affect system pressure/temperature readings.

Normal System Performance 72 Km/h (45 mph) - L61

Degrees*	Suction*	Discharge*	Outlet*
21°C (70°F)	207-227 kPa (30-33 psi)	593-675 kPa (86-98 psi)	6-11°C (42-52°F)
27°C (80°F)	207-213 kPa (30-31 psi)	758-827 kPa (110-120 psi)	6-14°C (43-57°F)
33°C (90°F)	207-213 kPa (30-31 psi)	1054-1171 kPa (153-170 psi)	7-9°C (45-49°F)
38°C (100°F)	193-213 kPa (28-31 psi)	1206-1378 kPa (175-200 psi)	7-11°C (45-52°F)
Degrees - If the ambient air temperature is Suction - and the low side gage should read Discharge - and the high side gage should read Outlet - and the right center air temperature should be

Normal System Performance Service Stall High Humidity - L61

Degrees*	Suction*	Discharge*	Outlet*
21°C (70°F)	200-207 kPa (29-30 psi)	758-999 kPa (110-145 psi)	8-9°C (47-48°F)
27°C (80°F)	193-200 kPa (28-29 psi)	1054-1206 kPa (153-175 psi)	7-8°C (44-46°F)
33°C (90°F)	186-200 kPa (27-29 psi)	1337-1929 kPa (194-280 psi)	8-9°C (47-49°F)
38°C (100°F)	179-193 kPa (26-28 psi)	1702-2412 kPa (247-350 psi)	10-11°C (50-51°F)

•

High humidity conditions affect the system performance by increased heat load on the system. This extra heat load will increase the discharge pressure and the outlet temperature. High humidity is defined as a relative humidity higher than 70 percent at 21°C (70°F), 60 percent at 27°C (80°F), 50 percent at 32°C (90°F), and 40 percent at 38°C (100°F).

•	This chart illustrates the effect the high humidity has on the Saturn air conditioning system. Use this chart to determine the normal system performance under high humidity conditions.

•	As a general rule, normal system operating under high humidity conditions will produce an outlet temperature of at least 20°F below the ambient air temperature.

General System Condition - Low Refrigerant Charge - L61

Degrees*

Suction*

Discharge*

Outlet *

21-38°C (70-100°F)

Normal to High

Low

Slightly Cool to Warm

Important: The system is operating with a low charge.

•	Confirm by touching the suction and the discharge pipe at the compressor. The suction pipe will be cool to warm and the discharge pipe will be warm to hot.

•	The pipe temperatures will vary with he ambient air temperature and the amount of the charge lost. The suction and the outlet temperatures will be warmer as more refrigerant is lost or ambient air temperature increases.

•	Leak test all the components and connections.

•	If the refrigerant charge level is unknown, reclaim, evacuate and recharge the system with 0.95 kg (2.09 lb) of R-134a.

•	Run another performance test.

Key: Poor Cooling at Higher Ambients.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

General System Condition Refrigerant/Oil Overcharge - L61

Degrees*

Suction*

Discharge*

Outlet*

21-38°C (70-100°F)

Normal to Slightly High

High

Cool to Warm

Important: The System may be operating in an overcharged condition.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be cool and the discharge pipe will be vary hot.

•	An overcharged condition will generate a poor and/or intermittent cooling complaint at higher ambient air temperatures. Intermittent complaints are caused by the pressure switch cycling the compressor ON and OFF.

•	Reclaim the system using an approved recovery system. Evacuate and recharge the system with 0.95 kg (2.09 lb) of R-134a.

•	Run another performance test.

•	An oil overcharge can occur if a compressor change is made without proper oil balancing. Review the vehicle service history for compressor service.

Key: The high pressure switch cycles the compressor on and off at high ambient air temperatures

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

Specific System Condition-Compressor No-Pump - L61

Degrees*

Suction*

Discharge*

Outlet*

21-38°C (70-100°F)

483-689 kPa (70-100 psi)

21-38°C (70-100°F)

Important: Ensure that the manifold gage set valves are closed.

Important: Most likely the vanes are not extending to the cylinder walls.

•	Run the engine at 2,000 RPM and cycle the compressor ON and OFF two or three times.

•	If the pressure remains static, engage the compressor and snap the engine throttle two or three times.

•	If the pressure still remains static, replace the compressor.

•	After the repair, return to the diagnostic flow chart.

Key: No change in the suction and the discharge pressures with the compressor engaged. The gage pressures will be almost equal.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

Specific System Condition - Compressor at Minimum Displacement - L61

Degrees*

Suction*

Discharge*

Outlet*

21°C (70°F)

289-338 kPa (42-49 psi)

668-792 kPa (97-115 psi)

15-18°C (59-65°F)

27°C (80°F)

317-365 kPa (46-53 psi)

827-930 kPa (120-135 psi)

17-20°C (63-68°F)

33°C (90°F)

379-434 kPa (55-63 psi)

937-1275 kPa (136-185 psi)

21-26°C (69-79°F)

38°C (100°F)

434-482 kPa (63-70 psi)

1109-1412 kPa (161-205 psi)

23-29°C (73-84°F)

Important: The compressor may be at minimum displacement.

•	This condition will be most noticeable at high ambients.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be warm and the discharge pipe will be warm to hot.

•	Confirm the charge level before replacing the compressor.

•	After the repair, return to the diagnostic flow chart.

Key: Increased suction pressure for a relatively low discharge pressure and high outlet temperatures.

Specific System Condition - Compressor at Maximum Displacement - L61

Degrees*

Suction*

Discharge*

Outlet*

21°C (70°F)

69-103 kPa (10-15 psi)

930-1068 kPa (135-155 psi)

5-1°C (23-34°F)

27°C (80°F)

76-131 kPa (11-19 psi)

1275-1378 (185-200 psi)

1-4°C (31-40°F)

33°C (90°F)

124-158 kPa (18-23 psi)

1378-1585 kPa (200-230 psi)

2-7°C (35-45°F)

38°C (100°F)

152-186 kPa (22-27 psi)

1592-2480 kPa (231-360 psi)

6-9°C (43-48°F)

Important: The compressor may be at maximum displacement.

•	This condition will be most noticeable at low ambients.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be very cold and the discharge pipe will be hot.

•	This condition could generate an intermittent cooling complaint along with reduced air flow because of evaporator freeze up at lower ambient air temperatures.

•	Replace the compressor.

•	After the repair, return to the diagnostic flow chart.

Key: Lower than normal suction pressure and outlet temperature at lower ambients and higher than normal discharge pressures.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

Specific System Condition - TXV Restricted - L61

Degrees*

Suction*

Discharge*

Outlet*

21°C (70°F)

179-193 kPa (26-28 psi)

710-744 kPa (103-108 psi)

18-22°C (65-72°F)

27°C (80°F)

179-200 kPa (26-29 psi)

868-1034 kPa (126-150 psi)

8-18°C (47-65°F)

33°C (90°F)

165-186 kPa (24-27 psi)

1096-1550 kPa (159-225 psi)

7-16°C (44-61°F)

38°C (100°F)

165-179 kPa (24-26 psi)

1364-1895 kPa (198-275 psi)

9-14°C (48-57°F)

Important: The degree of restriction will alter temperature and pressure readings.

Important: The thermal expansion valve (TXV) may be restricted.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be warm to cool at low ambients and cool to cold at high ambients. The discharge pipe will be warm to hot.

•	This condition can lead to compressor chatter due to lack of oil.

•	Replace the TXV.

•	After the repair, return to the diagnostic flow chart.

Key: Low suction pressure and higher than normal outlet air temperatures.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

Specific System Condition - TXV Open - L61

Degrees*

Suction*

Discharge*

Outlet*

21°C (70°F)

200-213 kPa (29-31 psi)

861-937 kPa (125-136 psi)

6-9°C (42-49°F)

27°C (80°F)

186-220 kPa (27-32 psi)

1171-1344 kPa (170-195 psi)

7-12°C (45-54°F)

33°C (90°F)

193-234 kPa (28-34 psi)

1364-1516 kPa (198-220 psi)

9-14°C (48-57°F)

38° (100°F)

234-303 kPa (34-44 psi)

1543-2170 kPa (224-315 psi)

15-17°C (59-63°F)

Important: The thermal expansion valve (TXV) may be open.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be cool to cold and the discharge pipe will be warm to hot.

•	This condition can lead to compressor chatter due to oil being flushed from the compressor.

•	Replace the TXV.

•	After the repair, return to the diagnostic flow chart.

Key: Higher than normal suction pressure, and higher than normal outlet temperatures.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

General System Condition - TXV Closed - L61

Degrees*

Suction*

Discharge*

Outlet*

21-38°C (70-100°F)

0-34 kPa (0-5 psi)

482-689 kPa (70-100 psi)

21-38°C (70-100°F)

Important: The thermal expansion valve (TXV) may be closed.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be warm and the discharge pipe will be warm to hot.

•	This condition may cause compressor damage due to the lack of oil circulation. Check the compressor operation.

•	Replace the TXV.

•	After the repair, return to the diagnostic flow chart.

Key: Near vacuum for suction pressure, low discharge pressure, and right center air grill near ambient.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

General System Condition - High or Low Side Restrictions - L61

Degrees*

Suction*

Discharge*

Outlet*

21-38°C (70-100°F)

Low

Cool to Warm

Important: Confirm the condition by a thorough physical and visual inspection of all lines and components.

•	If the restriction is between the compressor and the condenser, the discharge pressure will be higher than normal.

•	The temperature will be much colder on the down stream side of the restriction. Also look for possible frost.

•	Replace the restricted part.

•	After the repair, return to the diagnostic flow chart.

Key: Temperature drop across restriction in line or component

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

Normal System Performance Service Stall - L81

Degrees*	Suction*	Discharge*	Outlet*
21°C (70°F)	179-213 kPa (26-29 psi)	958-1275 kPa (139-185 psi)	5-8°C (41-46°F)
27°C (80°F)	172-207 kPa (25-28 psi)	1309-1516 kPa (190-220 psi)	6-9°C (42-48°F)
33°C (90°F)	172-200 kPa (25-27 psi)	1550-2343 kPa (225-340 psi)	7-9°C (45-48°F)
38°C (100°F)	172-200 kPa (25-27 psi)	1895-2343 kPa (275-340 psi)	7-12°C (45-53°F)
Degrees - If the ambient air temperature is Suction - and the low side gage should read Discharge - and the high side gage should read Outlet - and the right center air temperature should be

Important: Use a refrigerant identifier to verify refrigerant purity. Non-condensable gases or refrigerant substitutes will affect system pressure/temperature readings.

Normal System Performance 72 Km/h (45 mph) - L81

Degrees*	Suction*	Discharge*	Outlet*
21°C (70°F)	207-220 kPa (30-32 psi)	634-827 kPa (92-120 psi)	6-9°C (42-48°F)
27°C (80°F)	200-213 kPa (29-31 psi)	806-1034 kPa (117-150 psi)	7-10°C (44-50°F)
33°C (90°F)	193-207 kPa (28-30 psi)	999-1206 kPa (145-175 psi)	6-11°C (43-51°F)
38°C (100°F)	193-207 kPa (28-30 psi)	1275-1378 kPa (185-200 psi)	6-13°C (43-55°F)

Normal System Performance Service Stall High Humidity - L81

Degrees*	Suction*	Discharge*	Outlet*
21°C (70°F)	186-193 kPa (27-28 psi)	978-1378 kPa (142-200 psi)	7-8°C (44-46°F)
27°C (80°F)	193-200 kPa (28-29 psi)	1275-1585 kPa (185-230 psi)	8-9°C (46-49°F)
33°C (90°F)	186-193 kPa (27-28 psi)	1640-2480 kPa (238-360 psi)	9-11°C (49-52°F)
38°C (100°F)	186-200 kPa (27-29 psi)	1991-2515 kPa (289-365 psi)	11-13°C (52-56°F)
Degrees - If the ambient air temperature is Suction - and the low side gage should read Discharge - and the high side gage should read Outlet - and the right center air temperature should be

•

•	This chart illustrates the effect the high humidity has on the Saturn air conditioning system. Use this chart to determine the normal system performance under high humidity conditions.

•	As a general rule, normal system operating under high humidity conditions will produce an outlet temperature of at least 20°F below the ambient air temperature.

General System Condition - Low Refrigerant Charge - L81

Degrees*

Suction*

Discharge *

Outlet *

21-38°C (70-100°F)

Normal to High

Low

Slightly Cool to Warm

Important: The system is operating with a low charge.

•	Confirm by touching the suction and the discharge pipe at the compressor. The suction pipe will be cool to warm and the discharge pipe will be warm to hot.

•	The pipe temperatures will vary with he ambient air temperature and the amount of the charge lost. The suction and the outlet temperatures will be warmer as more refrigerant is lost or ambient air temperature increases.

•	Leak test all the components and connections.

•	If the refrigerant charge level is unknown, reclaim, evacuate and recharge the system with 0.95 kg (2.09 lb) of R-134a refrigerant.

•	Run another performance test.

Key: Poor Cooling at Higher Ambients.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

General System Condition Refrigerant/Oil Overcharge - L81

Degrees*

Suction*

Discharge*

Outlet*

21-38°C (70-100°F)

Normal to Slightly High

High

Cool to Warm

Important: The System may be operating in an overcharged condition.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be cool and the discharge pipe will be vary hot.

•	An overcharged condition will generate a poor and/or intermittent cooling complaint at higher ambient air temperatures. Intermittent complaints are caused by the pressure switch cycling the compressor ON and OFF.

•	Reclaim the system using an approved recovery system. Evacuate and recharge the system with 0.95 kg (2.09 lb) of R-134a refrigerant.

•	Run another performance test.

•	An oil overcharge can occur if a compressor change is made without proper oil balancing. Review the vehicle service history for compressor service.

Key: The high pressure switch cycles the compressor on and off at high ambient air temperatures.

Specific System Condition-Compressor No-Pump - L81

Degrees*

Suction*

Discharge*

Outlet*

21-38°C (70-100°F)

483-689 kPa (70-100 psi)

21-38°C (70-100°F)

Important: Ensure that the manifold gage set valves are closed.

Important: Most likely the vanes are not extending to the cylinder walls.

•	Run the engine at 2,000 RPM and cycle the compressor ON and OFF two or three times.

•	If the pressure remains static, engage the compressor and snap the engine throttle two or three times.

•	If the pressure still remains static, replace the compressor.

•	After the repair, return to the diagnostic flow chart.

Key: No change in the suction and the discharge pressures with the compressor engaged. The gage pressures will be almost equal.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

Specific System Condition - Compressor at Minimum Displacement - L81

Degrees*

Suction*

Discharge*

Outlet*

21°C (70°F)

317-358 kPa (46-52 psi)

717-861 kPa (104-125 psi)

17-21°C (62-69°F)

27°C (80°F)

358-400 kPa (52-58 psi)

854-1171 kPa (124-170 psi)

18-23°C (64-73°F)

33°C (90°F)

400-455 kPa (58-66 psi)

1013-1240 kPa (147-180 psi)

21-26°C (70-79°F)

38°C (100°F)

455-565 kPa (66-82 psi)

1144-1550 kPa (166-225 psi)

27-32°C (81-90°F)

Important: The compressor may be at minimum displacement.

•	This condition will be most noticeable at high ambients.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be warm and the discharge pipe will be warm to hot.

•	Confirm the charge level before replacing the compressor.

•	After the repair, return to the diagnostic flow chart.

Key: Increased suction pressure for a relatively low discharge pressure and high outlet temperatures.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

Specific System Condition - Compressor at Maximum Displacement - L81

Degrees*

Suction*

Discharge*

Outlet*

21°C (70°F)

110-124 kPa (16-18 psi)

1164-1240 kPa (169-180 psi)

3-6°C (37-42°F)

27°C (80°F)

138-158 kPa (20-23 psi)

1378-1654 (200-240 psi)

3-8°C (37-46°F)

33°C (90°F)

165-172 kPa (24-25 psi)

1598-2274 kPa (232-330 psi)

6-9°C (42-49°F)

38°C (100°F)

179-186 kPa (26-27 psi)

1902-2412 kPa (276-350 psi)

8-11°C (46-51°F)

Important: The compressor may be at maximum displacement.

•	This condition will be most noticeable at low ambients.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be very cold and the discharge pipe will be hot.

•	This condition could generate an intermittent cooling complaint along with reduced air flow because of evaporator freeze up at lower ambient air temperatures.

•	Replace the compressor.

•	After the repair, return to the diagnostic flow chart.

Key: Lower than normal suction pressure and outlet temperature at lower ambients and higher than normal discharge pressures.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

Specific System Condition - TXV Restricted - L81

Degrees*

Suction*

Discharge*

Outlet*

21°C (70°F)

200-213 kPa (27-29 psi)

806-1068 kPa (117-155 psi)

11-12°C (51-53°F)

27°C (80°F)

172-200 kPa (25-27 psi)

1123-1378 kPa (163-200 psi)

8-11°C (47-52°F)

33°C (90°F)

158-179 kPa (23-26 psi)

1337-1929 kPa (194-280 psi)

9-13°C (49-55°F)

38° (100°F)

165-179 kPa (24-26 psi)

1660-2412 kPa (241-350 psi)

9-14°C (48-58°F)

Important: The degree of restriction will alter temperature and pressure readings.

Important: The thermal expansion valve (TXV) may be restricted.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be warm to cool at low ambients and cool to cold at high ambients. The discharge pipe will be warm to hot.

•	This condition can lead to compressor chatter due to lack of oil.

•	Replace the TXV.

•	After the repair, return to the diagnostic flow chart.

Key: Low suction pressure and higher than normal outlet air temperatures.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

Specific System Condition - TXV Open - L81

Degrees*

Suction*

Discharge*

Outlet*

21°C (70°F)

186-207 kPa (27-30 psi)

1123-1178 kPa (163-171 psi)

8-11°C (47-51°F)

27°C (80°F)

193-220 kPa (28-32 psi)

1282-1309 kPa (186-190 psi)

9-12°C (48-54°F)

33°C (90°F)

220-255 kPa (32-37 psi)

1447-1723 kPa (210-250 psi)

8-17°C (47-63°F)

38° (100°F)

248-317 kPa (36-46 psi)

1778-2136 kPa (258-310 psi)

14-18°C (58-64°F)

Important: The thermal expansion valve (TXV) may be open.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be cool to cold and the discharge pipe will be warm to hot.

•	This condition can lead to compressor chatter due to oil being flushed from the compressor.

•	Replace the TXV.

•	After the repair, return to the diagnostic flow chart.

Key: Higher than normal suction pressure, and higher than normal outlet temperatures.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

General System Condition - TXV Closed - L81

Degrees*

Suction*

Discharge*

Outlet*

21-38°C (70-100°F)

0-34 kPa (0-5 psi)

482-689 kPa (70-100 psi)

21-38°C (70-100°F)

Important: The thermal expansion valve (TXV) may be closed.

•	Confirm by touching the suction and the discharge pipes at the compressor. The suction pipe will be warm and the discharge pipe will be warm to hot.

•	This condition may cause compressor damage due to the lack of oil circulation. Check the compressor operation.

•	Replace the TXV.

•	After the repair, return to the diagnostic flow chart.

Key: Near vacuum for suction pressure, low discharge pressure, and right center air grill near ambient.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be

General System Condition - High or Low Side Restrictions - L81

Degrees*

Suction*

Discharge*

Outlet*

21-38°C (70-100°F)

Low

Cool to Warm

Important: Confirm the condition by a thorough physical and visual inspection of all lines and components.

•	If the restriction is between the compressor and the condenser, the discharge pressure will be higher than normal.

•	The temperature will be much colder on the down stream side of the restriction. Also look for possible frost.

•	Replace the restricted part.

•	After the repair, return to the diagnostic flow chart.

Key: Temperature drop across restriction in line or component.

*Degrees - If the ambient air temperature is

*Suction - and the low side gage should read

*Discharge - and the high side gage should read

*Outlet - and the right center air temperature should be