Experiencing Poor Vacuum?
Ultimate vacuum will not be instantaneous. It is relative to pump capacity and system size. If it appears the rotary pump is not achieving high vacuum, check as follows:
Oil level correct when pumping.
All fitting hoses are tight and valves shut.
If no improvement is achieved, check with a known good McLeod gauge or electronic gauge as follows:
Remove pump from system.
Connect gauge to suction fitting positively sealed.
Run pump. A McLeod gauge should indicate a vacuum of between 50 and 1 micron. An electronic gauge will show approximately 250 to 20 micron after five minutes, depending on type of pump.
Cooling a recovery cylinder with your JAVAC XTR Pro or EVO unit
Your XTR Pro or EVO Series recovery unit can be used to PRE-cool (or SUB-cool) the recovery cylinder if the head pressure is too high to complete the recovery process. This can occur when working with certain refrigerants with a high vapour pressure in high ambient temperatures.
If the recovery process stalls out because of high head pressure, stop the recovery unit, shut off the hose valves and reconfigure the setup as shown below. This can also be done before starting the recovery process but it may have marginal long term effect.
NOTE: This will only work if there is at least 5 Kg of liquid in the recovery cylinder to develop the necessary pressure differential required.
POWER ON the recovery unit and ROTATE the DISCHARGE Valve (V3) to achieve a pressure differential of at least 700 Kpa between the LP Gauge and the HP Gauge. KEEP THE HP BELOW 2500 Kpa on the HP Gauge to ensure that the HP Cut-Off Switch will not actuate.
After several minutes of running, the cylinder will be cold. POWER OFF the recovery unit and reconfigure the setup for NORMAL RECOVERY. Repeat as needed.
Oils Aint Oils!
Why your pump needs Genuine JAVAC Oil.
It is extremely important to operate your vacuum pump using the correct viscosity oil as those which are either thinner or thicker, will cause damage and operational issues.
Oil Must be Changed When Contaminated
Oil contamination is usually indicated by poor vacuum reading, or a grey or milky appearance. Should liquids be accidentally allowed into the pump CHANGE OIL IMMEDIATELY. Your JAVAC High Vacuum Pump is a precision unit and oil is less expensive than pump service and repairs.
We take pride in every JAVAC Vacuum Pump and ensure you of our long-term interest in our product's reliability.
Recovering Gas from a Vehicle
When recovering gas from a vehicle ensure it is done at a moderate pace. Most automotive A/C systems take on average 100-150ml of oil. This oil is circulated with the gas around the system and at any one time. If too much oil is removed from a system the compressor will fail prematurely. Most automotive recovery machines have an integrated oil separator. This separator is only so efficient at extracting the oil from recovered gas. If gas is recovered too fast, users run the risk of the oil being pumped into the reclaim bottle and thereby are unaware of how much oil the system is short of.
As a general rule, recover from the low side of the vehicle A/C system first. Limit the speed of recovery by throttling the tap on the recovery unit. When the majority of the gas has been recovered, the high side may be used to recover. This ensures no liquid refrigerant carries excessive amounts of oil back into the recovery unit.
Charging in the Winter
Using your air conditioning charging station in the winter months can present it's own problems. The refrigeration gas (R134a) does not flow too well if the external temperature drops in the workshop. Some machines have their own on-board heaters but others rely on recovering some refrigerant from the vehicle or from a supply cylinder. One of the benefits of recovering and recycling refrigerant is the heat generated through the compressor. The charging station works exactly the same way as a vehicle; if you draw gas from a low pressure area and compress it, the low pressure side gets cold and the high pressure side gets hot. This hot high pressure liquid that comes from the recovery side gives us a benefit when charging into the car as the liquid races into the system quicker.
One of the drawbacks with charging liquid refrigerant into an evacuated system is as soon as the liquid is released it wants to expand into a gas and equalise the pressure between the car and the charging station. If this takes place before the full charge has been delivered then the station effectively undercharges the car and the charge is not complete. A simple trick to rectify this is to close the red HP valve on the station or the HP coupler and start the car. The compressor on the vehicle will then pull the rest of the refrigerant into the vehicle and finish the charge. The gas charge is usually weighed in from a scale platform on a modern machine and the scale doesn't care how the refrigerant is decanted.
If you find that there is a regular problem with charging then it might be an idea to check that the vacuum pump is in good condition. The oil level and oil condition is critical. The vacuum pump oil lubricates the pump and provides the seal for the pump blades. If the oil level is too low the seal breaks down and the high vacuum required cannot be reached. The quality of the oil is also important.
A poor vacuum can cause many problems because it does not dehydrate the system properly. Any moisture in the cars system can be devastating as the combination of R134a and moisture creates hydrochloric acid. This quickly saturates the filter dryer making it useless and then starts to destroy the whole system from the inside out.
With the Winter months being cold and damp, moisture is very difficult to keep out of an open system, especially if the vehicle has been damaged and stored in compound for a while. Because the system is effectively charged with refrigerant (R134a) as soon as it escapes and evaporates it leaves the inside of the system very dry. Moisture is automatically attracted to the dry areas and considerable amounts of water can form inside the pipes and condenser. This is unavoidable and only an extensive evacuation can rectify it. In this case a new filter dryer must be fitted and the system evacuated immediately. If we break into the system and have to leave it for any length of time then taping the open hose ends up with tape can be a great help. This obviously stops moisture and dust from entering the system and causing unnecessary contamination.
A very cold car can be difficult to recover the gas from. This can be due to the pressure being very low in the system and warming the car up is a great help. Also, if the recovery cylinder has picked up air the pressure increases and the compressor will struggle. As a tip, it is always worth keeping the new supply cylinder near the station so that they are at the same temperature.
For more information or assistance with any refrigerant reclaiming enquiry contact JAVAC.
Decrease Your Refrigeration Recovery Times
In most recovery applications we are all in a hurry to recover the most amount of refrigerant in the quickest time available. This can be made easier by using the Push Pull method. Otherwise you must ensure that your recovery unit does have the refrigerant throttle to it via the manifold to prevent liquid slugging which will cause damage to the compressor.
In all applications you should ensure if possible to have your cylinder under vacuum and as cool as possible. This will also help speed up the recovery process.
What is the Push Pull Method?
In simple terms you draw vapour off the top of your recovery cylinder, run it through your recovery unit and then back into the system your are recovering from.
Next run a hose from the liquid dipper tube on your receiver to the liquid in your bottle.
This method is only useful when more than 7 Kg of liquid is known to be in the system and it can be easily isolated.
My Vacuum Gauge Seems Inaccurate
My vacuum gauge does not seem to be accurate... How can you tell and what device do you have to measure it against?
If you have another vacuum gauge, you can use this to reference against on the same system. Your vacuum gauge may have had positive pressure and this could have possibly damaged the internals of your gauge.
Can your gauge be serviced? YES, in most cases they can. We can calibrate and check most gauges at our Service department.
General Maintenance for Recovery Machines
The actual requirements on JAVAC Recovery Machines are minimal but important!
Keep the unit clean by wiping it down with a damp cloth to remove dirt, oils, etc. prior to storage for the day. Standard household detergent or isopropyl alcohol may be used if the unit is particularly dirty; in all cases, exercise care to prevent liquids from entering the unit. Gasoline and other solvents are to be avoided as they can damage the plastic enclosure and are hazardous.
Clean inlet particle filter regularly. Discard internal filter screen if it is heavily contaminated and replace with a new screen.
Ensure that the Inlet and Discharge ports are protected and kept clean by replacing the plastic caps after every use. For best results, keep a FILTER permanently connected to the
Change HOSES periodically as they develop leaks and a build-up of contaminants over time. Change hoses at least once per season.
When storing the recovery machine for the season, or for long periods of time, PURGE the unit with an inert gas such as Nitrogen.
When performance falls off it is likely that the compressor seals require replacing. This is normal with use and may occur after a year or two or more often, depending upon the conditions that are prevalent during the recovery operations.
Operation of Gas Ballast Valve