INFORMATION - PUREGUARD 2 OPERATING ALERT. Buick Coachbuilder 1992

SUBJECT: INFORMATION - PUREGUARD 2 OPERATING ALERT

MODELS: 1998 AND PRIOR PASSENGER CARS AND TRUCKS WITH R134A A/C SYSTEMS

A NUMBER OF PUREGUARD 2'S HAVE BEEN RETURNED FROM THE FIELD AS THE RESULT OF DAMAGE FROM FLOODING THE UNIT WITH OIL AND LIQUID REFRIGERANT. IMPROPER SERVICE PROCEDURES AND UNIQUE A/C SERVICE CONDITIONS CAN CAUSE THIS. TO ENSURE OIL AND LIQUID REFRIGERANT NEVER ENTER THE PUREGUARD 2, A PROTECTIVE DEVICE, CALLED J-41810-100A ACTIVE FLOW CONTROL (AFC), HAS BEEN SHIPPED TO EVERY GENERAL MOTORS DEALERSHIP. THE AFC MUST BE INSTALLED TO PREVENT DAMAGE TO THE PUREGUARD 2.

TO ASSURE MAXIMUM PERFORMANCE OF YOUR PUREGUARD 2 REFRIGERANT IDENTIFIER AND ACR4 RECOVERY, RECYCLE AND RECHARGING STATION, BELOW ARE PERFORMANCE TIPS THAT NEED TO BE FOLLOWED. PLACE A COPY OF THIS BULLETIN WITH THE ACR4 INSTRUCTION MANUAL IN THE SIDE POCKET OF THE ACR4.

REFRIGERANT RECOVERY

O ALWAYS RECOVER REFRIGERANT FROM BOTH THE HIGH AND LOW SIDE OF THE VEHICLE'S A/C SYSTEM SIMULTANEOUSLY. THIS WILL SHORTEN THE RECOVERY PROCESS AND ENSURE AS MUCH REFRIGERANT AS POSSIBLE IS REMOVED FROM THE SYSTEM.

O THE PUREGUARD 2 IS DESIGNED TO SAMPLE REFRIGERANT VAPOR FROM THE LOW SIDE OF THE VEHICLE DURING THE RECOVERY PROCESS. A PRESSURE SWITCH IN THE HIGH SIDE IS USED TO SENSE ANY ATTEMPT TO BYPASS THE PURITY TEST. IF PRESSURE IS SENSED IN THE HIGH SIDE ONLY, AN "ALARM" SOUNDS AND RECOVERY IS HALTED. WHEN 30 PSI IS SENSED IN THE LOW SIDE, POWER IS RESTORED TO THE ACR4. RESET OF THE PUREGUARD 2 IS NOT NECESSARY AND ELIMINATES WAITING FOR THE WARM-UP CYCLE.

O THERE HAVE BEEN REPORTS OF THE PUREGUARD 2 BEING REMOVED FROM THE ACR4 DUE TO A MISINTERPRETATION OF THE RED EXCESS AIR LIGHT. THE LIGHT INDICATES THE PRESENCE OF HIGH LEVELS OF AIR IN THE REFRIGERANT STORAGE TANK, BUT IT DOES NOT STOP REFRIGERANT RECOVERY OR INTERFERE WITH THE OPERATION OF THE ACR4. A HIGH PERCENTAGE OF AIR WILL INCREASE TANK PRESSURE AND CAN SLOW DOWN OR IN SOME CASES, STOP REFRIGERANT RECOVERY. EXCESS AIR SHOULD BE PURGED FROM THE TANK PRIOR TO CHARGING A VEHICLE. THIS BULLETIN INCLUDES A PROCEDURE FOR QUICK ELIMINATION OF EXCESS AIR WITHOUT OPERATING THE VACUUM OR RECYCLE MODES.

THE RED EXCESS AIR LIGHT TURNS ON WHEN THE AIR LEVEL MEASURED IN THE VAPOR AT THE TOP OF THE TANK REACHES 6%. WHEN CHARGING A VEHICLE, LIQUID REFRIGERANT IS DRAWN FROM THE BOTTOM OF THE TANK WHICH CONTAINS A LOWER PERCENTAGE OF AIR. AS THE AIR CONTENT INCREASES, THE RISE IN TANK PRESSURE FORCES AIR INTO THE LIQUID REFRIGERANT IN THE TANK. AIR IN EXCESS OF 4% IN THE VEHICLE'S A/C SYSTEM CAN CAUSE CONCERNS.

O SOME GM VEHICLES HAVE A/C SYSTEMS THAT ARE DESIGNED WITH THE LOW SIDE SERVICE PORT LOCATED AT A VERY LOW SPOT IN THE SYSTEM. LIQUID REFRIGERANT WILL "PUDDLE" IN THIS LOCATION WHEN THE A/C SYSTEM IS NOT OPERATING. IF THE LOW SIDE SERVICE HOSE IS CONNECTED AND THE RECOVERY PROCESS STARTED, A SLUG OF LIQUID MAY BE DELIVERED TO THE PUREGUARD 2. TO ENSURE OIL AND LIQUID REFRIGERANT NEVER ENTER THE PUREGUARD 2, MAKE SURE THE AFC IS INSTALLED.

OIL INJECTION AND REFRIGERANT CHARGING

O WHEN USING THE ACR4 RECOVERY STATION, ALWAYS CLOSE BOTH LOW AND HIGH SIDE MANIFOLD GAUGE VALVES ON THE ACR4 CONTROL PANEL AS SOON AS THE VACUUM PUMP CYCLE IS COMPLETE. TO INJECT OIL FROM THE OIL BOTTLE ON THE BACK OF THE ACR4, SIMPLY OPEN THE OIL INJECTION VALVE; OIL AUTOMATICALLY FLOWS THROUGH THE HIGH SIDE SERVICE HOSE AND INTO THE VEHICLE WITHOUT ENTERING THE MANIFOLD GAUGE ASSEMBLY.

O ALWAYS CHARGE REFRIGERANT THROUGH THE HIGH SIDE ONLY. GENERAL MOTORS REQUIRES HIGH SIDE CHARGING ON ALL GM VEHICLES, AND THE FLOW OF LIQUID REFRIGERANT THROUGH THE HIGH SIDE IS NECESSARY TO WASH ANY REMAINING OIL IN THE HIGH SIDE SERVICE HOSE INTO THE VEHICLE.

O THERE ARE SEVERAL OIL AND TRACER DYE INJECTORS ON THE MARKET THAT ARE DESIGNED TO BE INSTALLED BETWEEN THE ACR4 AND THE LOW SIDE SERVICE HOSE. DO NOT USE THIS TYPE OF INJECTOR.

O OIL AND TRACER DYE INJECTORS DESIGNED TO CONNECT DIRECTLY TO THE VEHICLE'S LOW SIDE SERVICE PORT CAN BE USED. HOWEVER, YOU MUST RUN THE VEHICLE'S A/C SYSTEM LONG ENOUGH TO ENSURE THE OIL OR DYE IS DISTRIBUTED EVENLY THROUGHOUT THE A/C SYSTEM PRIOR TO RECOVERING REFRIGERANT FROM THE VEHICLE.

O INDICATIONS THAT TECHNICIANS ARE INCORRECTLY INJECTING OIL AND LEAK DYE ARE:

- LARGE AMOUNTS OF OIL OR DYE DRAINED FROM THE OIL SEPARATOR AFTER RECOVERY.

- VACUUM PUMP OIL LEVEL ABOVE THE SIGHT GLASS OR TINTED THE COLOR OF DYE.

- LARGE AMOUNTS OF OIL AND DYE RESIDUE COVERING ACR4.

- LIQUID FLOODING OF THE PUREGUARD 2.

THIS OCCURS BECAUSE OIL AND DYE INTENDED FOR THE VEHICLE'S A/C SYSTEM IS TRAPPED IN THE SERVICE HOSE. THE NEXT TIME REFRIGERANT RECOVERY IS PERFORMED, THE OIL AND DYE ARE DRAWN BACK INTO THE ACR4.

O TO ENSURE THE VEHICLE RECEIVES THE CORRECT REFRIGERANT CHARGE, THE HOSE CLEARING PROCEDURE MUST BE PERFORMED EVERY TIME A VEHICLE IS CHARGED. REFER TO THE ACR4 MANUAL FOR THIS PROCEDURE. FAILURE TO DO SO WILL LEAVE A SIGNIFICANT AMOUNT OF LIQUID REFRIGERANT IN THE ACR4 SERVICE HOSE.

O DISCONNECT THE HIGH AND LOW SIDE SERVICE HOSES FROM THE VEHICLE AS SOON AS A/C SERVICE IS COMPLETE. FAILURE TO DISCONNECT THE COUPLERS WILL ALLOW THE PUREGUARD 2 TO CONTINUE TO TAKE SMALL SAMPLES OF REFRIGERANT AND TEST IT. OVER TIME, THE CHARGE LEVEL IN THE VEHICLE WILL DECREASE TO A POINT WHERE IT WILL BE NECESSARY TO RECHARGE THE SYSTEM AGAIN DUE TO LOSS OF REFRIGERANT.

O AN UNSUCCESSFUL CHARGING PROCEDURE OCCURS WHEN THE REFRIGERANT DOES NOT COMPLETELY TRANSFER FROM THE ACR4 TANK INTO THE VEHICLE. UNSUCCESSFUL CHARGING CAN BE AVOIDED BY RUNNING THE VACUUM PUMP FOR THE FULL 15-MINUTE VACUUM CYCLE AND CHARGING THE VEHICLE AS SOON AFTER THE VACUUM CYCLE AS POSSIBLE. THE REFRIGERANT IS RECYCLED DURING THE VACUUM CYCLE BUILDING UP HEAT AND PRESSURE WHICH COMPLETELY FORCES THE ENTIRE CHARGE INTO THE VEHICLE.

ADDITIONAL ACR4 OPERATION AND MAINTENANCE TIPS

O BE SURE BOTH VALVES ON THE ACR4 REFRIGERANT TANK ARE OPEN BEFORE BEGINNING ANY A/C RECOVERY, RECYCLING, VACUUM AND RECHARGING PROCEDURES. THIS PREVENTS PRESSURE BUILD UP IN THE ACR4 AND ALLOWS FOR FREE FLOW OF REFRIGERANT IN AND OUT OF THE TANK.

O ACR4 VACUUM PUMP OIL MUST BE CHANGED EVERY 10 HOURS OF PUMP OPERATION. THE ACR4 HAS AN INTERNAL TIMER TO NOTIFY WHEN THE OIL SHOULD BE CHANGED. THE OIL LEVEL MUST BE SET TO THE CORRECT LEVEL PER THE ACR4 OPERATING MANUAL. AN OVER-FILLED RESERVOIR WILL CAUSE SLOW STARTUP OF THE PUMP, DRAW EXCESS CURRENT AND BURNOUT THE 15 AMP DELAY REACTION FUSE IN THE PUREGUARD 2. THE PUMP OIL LEVEL MUST BE CHECKED ON A WEEKLY BASIS IF THERE IS FREQUENT FUSE BURNOUT.

TANK-TO-TANK REFRIGERANT TRANSFER

O WHEN ADDING REFRIGERANT FROM A NEW TANK INTO THE ACR4 TANK, A HOSE CLEARING PROCEDURE MUST BE DONE TO LOWER THE HIGH SIDE PRESSURE BELOW 50 PSI. THIS DEACTIVATES THE LOW SIDE ALARM. IF HIGH SIDE PRESSURE IS ABOVE 50 PSI WHILE LOW SIDE PRESSURE IS BELOW 30 PSI, THE LOW SIDE ALARM WILL SOUND AND THE PUREGUARD 2 WILL TURN THE ACR4 OFF BEFORE REFRIGERANT TRANSFER IS COMPLETE. REFER TO PAGES 17-18 OF THE ACR4 OPERATING INSTRUCTIONS MANUAL FOR A DETAILED PROCEDURE ON ADDING REFRIGERANT.

EXCESS AIR IN TANK

O DO NOT SHORTCUT THE PRE-PROGRAMMED, 15 MINUTE VACUUM PUMP CYCLE. SHORT CUTTING DOES NOT ALLOW THE ACR4 AUTOMATIC AIR PURGE CIRCUIT TO FULLY EXPEL THE AIR IN THE ACR4 TANK. SHORT CUTTING WILL EVENTUALLY LEAD TO ILLUMINATION OF THE TANK "EXCESS AIR" LIGHT ON THE PUREGUARD 2.

O THE QUICK CONNECT VALVES ON THE ACR4 RED AND BLUE SERVICE HOSES MUST BE CLOSED (ROTATED OUTWARD) WHEN THEY ARE ATTACHED TO THE STORAGE FITTINGS ON THE ACR4. OPEN VALVES WILL ALLOW EXCESS AIR TO ENTER THE STORAGE TANK DURING CERTAIN ACR4 OPERATING MODES.

O THE ACTIVE FLOW CONTROL ADDS ADDITIONAL HOSE AND LINE FITTINGS. THESE CONNECTION POINTS ARE AREAS FOR POSSIBLE LEAKS. PLIERS SHOULD BE USED TO TIGHTEN ALL ACR4 FITTINGS AND PERIODIC CHECKS SHOULD BE MADE TO ASSURE NONE HAVE LOOSENED. LOOSE FITTINGS CAN CAUSE REFRIGERANT LOSS OR EXCESS AIR IN THE STORAGE TANK. BE CAREFUL NOT TO OVER TORQUE AND DESTROY FITTINGS.

O HIGH LEVELS OF EXCESS AIR ARE NOT QUICKLY PURGED OUT OF THE RECOVERY RECHARGING STATION TANK. IT COULD TAKE 1 WEEK OF PURGING 4 TIMES PER DAY BEFORE THE RED "EXCESS AIR" LIGHT TURNS OFF. YOU MUST HAVE PATIENCE.

O USING THE FOLLOWING PROCEDURE TO MANUALLY OPEN AND CLOSE THE AIR PURGE VALVE IN THE ACR4 CAN ACCELERATE REMOVAL OF HIGH LEVELS OF EXCESS AIR. THIS IS MOST EFFECTIVE IF DONE FIRST THING IN THE MORNING BEFORE THE REFRIGERANT IS AGITATED BY ANY VEHICLE RECOVERY, VACUUM OR RECYCLING PROCEDURES.

1. WITH THE ACR4 POWERED UP, ON THE CONTROL PANEL, PRESS "SHIFT" AND "ENTER" KEYS SIMULTANEOUSLY. SCREEN WILL GO BLANK.

2. PRESS "SHIFT" AND "CHARGE" KEYS SIMULTANEOUSLY. "D2" WILL DISPLAY ON SCREEN.

3. PRESS "1" KEY. "01" WILL DISPLAY AND PURGE VALVE SOLENOID WILL CLICK. EXCESS AIR WILL BE VENTED FROM THE TANK BUT THIS PROCEDURE DOES NOT VENT ANY REFRIGERANT TO ATMOSPHERE. THE AUTO PURGE MECHANISM WILL CLOSE AN INTERNAL VALVE WHEN THE AIR CONTENT REACHES A MINIMAL LEVEL.

PRESS "SHIFT" KEY TO EXIT THE MANUAL AIR PURGE MODE.

TANK PRESSURE CAN BE MEASURED USING THE HIGH SIDE MANIFOLD GAUGE IN THE ACR4 BY SHIFTING TO THE CHARGE MODE, SETTING A CHARGE WEIGHT OF 0.50 LB. AND PRESSING THE "ENTER" KEY, THEN PRESSING THE "CHARGE" KEY. THE ACR4 VALVES WILL OPEN AND FILL THE LINES WITH REFRIGERANT AT TANK PRESSURE. WITH THE HIGH SIDE GAUGE VALVE ON THE CONTROL PANEL OPEN, READ THE PRESSURE IMMEDIATELY FOR AN ACCURATE PRESSURE MEASUREMENT BECAUSE AS THE REFRIGERANT BEGINS TO COOL IN THE LINES, THE PRESSURE WILL DECREASE. AT AN AMBIENT ROOM TEMPERATURE OF 70 DEGREES FAHRENHEIT (21 DEGREES CELSIUS), THE PRESSURE IN A TANK OF R134A WITH NO AIR WILL BE BETWEEN 70 AND 80 PSI. THE CORRELATION BETWEEN PRESSURE AND TEMPERATURE IS APPROXIMATELY 1 PSI FOR EVERY 1 DEGREE INCREASE.

PUREGUARD 2 ERROR CODES

O CODE 1

INDICATES THE SENSORS INSIDE THE PUREGUARD 2 ARE NOT PROPERLY STABILIZED. THIS ERROR CODE CAN BE CAUSED BY HIGH LEVELS OF ELECTRICAL INTERFERENCE, SUDDEN CHANGES IN PRESSURE OR TEMPERATURE, OR COMPONENT FAILURE. THE ERROR MAY SELF-CLEAR BY TURNING THE TESTER OFF AND ON. IF THIS DOES NOT CLEAR THE ERROR, INTERNAL PARTS MAY REQUIRE SERVICE.

O CODE 2

INDICATES ONE OR MORE OF THE SENSORS ARE OUTPUTTING VOLTAGE OUTSIDE OF THE CALIBRATION RANGE. THIS ERROR CODE CAN BE CAUSED BY A SUDDEN CHANGE IN AMBIENT TEMPERATURE OR OPERATION OF THE PUREGUARD 2 OUT OF THE TEMPERATURE RANGE OF 32 - 120 F (0 - 49 C). ALLOW THE TESTER TO STABILIZE IN THE DESIRED TEMPERATURE RANGE WHILE POWERED OFF. AFTER TURNING TESTER ON, IF THE ERROR CODE DOES NOT CLEAR, INTERNAL PARTS MAY REQUIRE SERVICE.

O CODE 3 (WITH NO RED IN TOP PANEL FILTER)

INDICATES ONE OR MORE OF THE SENSORS DID NOT REACH THE CORRECT SENSITIVITY LEVEL DURING CALIBRATION. THIS ERROR CODE CAN BE CAUSED BY A SUDDEN CHANGE IN AMBIENT TEMPERATURE, POOR AIRFLOW TO THE SENSORS OR CONTAMINATED CALIBRATION AIR AT THE SENSORS. VERIFY THE SURROUNDING AIR IN THE AREA IS NOT CONTAMINATED BY REFRIGERANT VAPORS OR GAS FUMES (HYDROCARBONS). VENTILATE THE AREA TO BRING IN FRESH AIR. INSPECT THE TESTER'S AIR INTAKE PORT TO VERIFY NO OBSTRUCTIONS OR CLOGGING EXIST. POWER THE TESTER AND VERIFY FLOW OUT THE EXHAUST PORT DURING CALIBRATION. THE EXHAUST PORT IS A 1/16 IN. (1.5 MM) HOLE LOCATED ON THE LEFT SIDE OF THE TESTER. AFTER TURNING TESTER ON, IF THE ERROR CODE DOES NOT CLEAR, INTERNAL PARTS MAY REQUIRE SERVICE.

O CODE 3 (WITH RED IN TOP PANEL FILTER)

INDICATES OIL OR LIQUID REFRIGERANT WAS CHARGED INTO THE VEHICLE AND HAS CONTAMINATED THE FILTER AND THE SENSORS IN THE PUREGUARD 2. THE TESTER IS DAMAGED AND MUST BE SERVICED OR REPLACED.

ACTIVE FLOW CONTROL

THE J-41810-100A ACTIVE FLOW CONTROL (AFC) PROTECTS THE PUREGUARD 2 FROM DAMAGE CAUSED BY FLOODING FROM LIQUID REFRIGERANT, OIL OR LEAK DYE. A 1 AMP DELAY REACTION FUSE PROTECTS THE INTERNAL ELECTRONICS IN THE AFC. THE CHANCE THAT THIS FUSE WILL BURN OUT IS VERY MINIMAL BUT IF IT DOES, IT CAN BE EASILY DIAGNOSED AS FOLLOWS:

O THE RED LIGHT IN THE AFC WILL BE ON.

O THE PUREGUARD 2 WILL GO THROUGH THE WARM-UP PROCEDURE AND TEST THE ACR4 TANK.

O THE MANIFOLD GAUGES WILL SHOW A/C SYSTEM PRESSURE (IF THERE IS REFRIGERANT LEFT IN THE SYSTEM), BUT THE PUREGUARD 2 WILL NOT RUN A TEST EVEN THOUGH THE LOW SIDE GAUGE SHOWS OVER 30 PSI OF PRESSURE.

O THE FAIL-SAFE DESIGN OF THE AFC KEEPS ITS INTERNAL SOLENOID VALVE CLOSED IN A "NO POWER" CONDITION AND NO REFRIGERANT WILL FLOW INTO THE PUREGUARD 2.

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GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.