Charges as follows R134A = 1.8 lbs. R12 = 2.0 lbs.
No additional oil is necessary in new compressors

• III. TYPICAL PROBLEMS ENCOUNTERED IN CHARGING SYSTEMS
•  
• A. NOISY COMPRESSOR
• 1. A noisy compressor is generally caused by over charging the system or introducing outside air into the system.
•       a.  If a system is over charged both gauges will read abnormally high readings.  This is causing a feedback pressure on the compressor, causing it to rattle or shake from the increased cylinder head pressure. System must be evacuated according to weight specifications.
•       b. If air is introduced into the system during the charging process, it will introduce moisture that will cause ice to form in the refrigerant flow and will cause the compressor to rattle or growl under acceleration.  System must be evacuated and re-charged to the exact weight specifications making sure to bleed any air from lines when introducing the refrigerant.
•  B. SYSTEM NOT COOLING
•  1. There are numerous factors that can cause the cooling to be less than optimal.
•       a. Improper charge in the system - Improper charging is the number one cause of system failure.  The pressure readings should be taken before any determination can be made.  High or low readings in direct proportion to the normal pressures (see sect. II) will tell you if the charge is too high or low.  Excessive system pressure can also cause vibrations and whistling noise from the expansion valve and refrigerant lines.
•  
•      b. Heater control valve installation - Installing the heater control valve in the incorrect hose will allow water to collect in the unit. The heater control is a directional valve; make sure the water flow is with the direction of the arrow.  As the engine heats up the water transfers the heat to the coil, thus overpowering the a/c coil.  A leaking or faulty valve will have a more pronounced affect on the unit’s cooling ability.  Installing the valve improperly (such as having the flow reversed) will allow water to flow through, thus inhibiting cooling.  Check for heat transfer by disconnecting hose from the system completely. By running down the road with the hose looped back through the motor, you eliminate the possibility of heat transfer to the unit.  Move or replace the valve if necessary.
•  
•     c. Evaporator freezing - Freezing can occur both externally and internally on an evaporator core.
•   External freeze-up occurs when the coil cannot effectively displace the condensation on the outsides of the fins and the water forms to ice (the evaporator core resembles a block of solid ice) it restricts the flow of air that can pass through it, which gives the illusion of the air conditioning system not functioning.  The common cause of external freezing is the setting of the thermostat and the presence of high humidity in the passenger compartment.  All the door and window seals should be checked in the event of constant freeze-up.  A thermostat is provided with all units to control the cycling of the compressor. The rotary-type thermostat should be turned the entire way clockwise and then turned back counter clockwise an eight of a turn.  The lever type thermostat should be backed away from the cold position slightly.
•   Internal freeze-up occurs when there is too much moisture inside the system.  The symptoms of internal freeze-up often surface after extended highway driving.  The volume of air stays constant, but the temperature of the air gradually rises.  When this freezing occurs the low side pressure will drop, eventually going into a vacuum.  At this point, a professional who will evacuate the system and charge the drier should check the system.
•  
•      d.  Inadequate airflow to condenser - The condenser works best in front of the radiator with a large supply of fresh air.  Abnormally high pressure will result from improper airflow.  Check the airflow requirements by placing a large capacity fan in front of the condenser, and running cool water over the surface. If the pressure drops significantly, this will indicate the need for better airflow.
•  
•      e.  Incorrect or inadequate condenser capacity - Incorrect condenser capacity will cause abnormally high head pressure.  Vintage Air recommends at least 300 cubic inches of fin area on a double-pass (two rows of tubes) condenser. (This can be measured by multiplying the height times the width times the thickness.)  This rule only applies to the tube and fin style; the efficiency of the superflow design allows the use of a smaller area.  A quick test that can be performed is to run cool water over the condenser while the system is operating, if the pressure decreases significantly, it is likely an airflow or capacity problem.
•  
•      f.  Expansion valve failure - An expansion valve failure is generally caused by dirt or debris entering the system during assembly.  If an expansion valve fails it will be indicated by abnormal gauge readings.  A valve that is blocked will be indicated by the high side that is usually high, while the low side will be usually low or may even go into a vacuum.  A valve that is stuck open will be indicated by both the high and low pressures rising to unusually high readings, seeming to move toward equal readings on the gauges.
•  
•      g.  Restrictions in system - A restriction in the cooling system will cause abnormal readings on the gauges.  A high-side restriction (between the compressor and the drier inlet) will be indicated by the discharge gauges reading excessively high.
•  
• These simple tests can be performed by a local shop and can help determine the extent of the systems problem.  If further assistance is needed, the Vintage Air tech line is (210) 654-7171.  If you have performed the initial test, please document results and readings before calling our technical line, it will help us solve the problem faster.
   

Vintage Air Service Procedure Guide without Recovery and Charge Station

Finish installation. If using new Sanden Compressor, do not add oil to system.  New Sanden Compressors are pre-charged with 7.2 oz of PAG Oil.

Put gauges on car.

Evacuate for 30 to 60 minutes, system should reach at least 29” inches of vacuum for 5 minutes (with room temperature at 85° or warmer or components heated).

Turn off vacuum pump, close valves and watch for vacuum drop as a clean leak check.

Do not start engine yet. Open both sides for a static charge. Charge into hi & low side with proper charge.  If refrigerant does not continue to flow, you may want to immerse refrigerant container (a little over half way) in a pan of warm water (up to 100° F) to complete static charge.

After proper charging, turn compressor over by hand 5 or 6 times before operating system.

If charging without warm water assist, charge through both sides as long as refrigerant will flow into system.  Turn compressor over by hand 5 or 6 times and close high side valve.

Start engine and finish charging through low side until system is charged with proper amount. Vintage Air systems require 1.8 lbs. (28.8 oz) of 134a Refrigerant.

Leak check and evaluation performance.

   *Doors & windows closed

   *Med./Hi blower

   *Engine RPM - 1500

   *Duct temp. - 42-48°

   *Pressures stabilized

   *Hi-side - 2X ambient + 10 to 20%

   *Low side - 8 to 15 lbs. In steady state to cycle (HFC-134a)

Notes:

Gas charging is safest; however, most compressors today do have anti-slug valves.  Always charge with manufacturers recommended charge. If you don't think the charge is working correctly, call Vintage Air.

Oil:

New compressor - no additional oil needed - if using remote condenser or rear-mounted system, call Vintage Air for advice on possible additional refrigerant.

Used compressors - call Vintage Air for Leak check - dye - soap/water Recommendations.

Inject a quality leak detection dye at time of charging.

Bead lock fittings crimped with (bubble crimp) crimping tool is best option with barrier hose.

NOTE: This procedure applies when using complete Vintage Air System only.

Thanks to Vintage Air for a really helpful article ... for information about Vintage Air Products visit their website

Click Here to go back to  Heat / Air  Menu Page

IMPORTANT NOTICE: All content in the articles in this section are the property of the author of the article and all advice and instructions are intended to be just basic guidelines for the undertaking of any project, and not intended for use by individuals who are not experienced in the particular field. We advise that you contact the manufacturer of any product or tool you are using for complete instructions. We also advise you to always use the appropriate safety equipment for the tools and products you are using. Hotrodhotline.com and its contributors disclaim any responsibility for the consequences of using the articles or procedures described in any of the articles in this section and by using this site you agree to these terms. No portion of any of these articles may be used without the written permission of HotRodHotLine.com and the Author.

Copyright 2007-2011  Hotrodhotline.com   All Rights Reserved
No Portion may be used without our written permission
Contact Us:    877-700-2468   or   208-562-0470
230 S. Cole Rd, Boise, ID  83709