FAQ

R 1234yf can be flammable when it is present in certain quantities and comes in contact with oxygen. Therefore, do keep the A/C service unit away from open flames or other sources of ignition in case of damage. The refrigerant itself is nontoxic. However, like any other gas, it replaces the oxygen needed for breathing. Should refrigerant escape, keep your calm, leave the place and make sure there is sufficient supply of fresh air. As usual, you should wear suitable protective clothing and equipment (goggles and gloves) when dealing with refrigerant. These are included with each service station.

During the operator training, our technician will, among other things, make you familiar with the following issues:

• Switch the unit on and let it start up. Do not yet connect the service station to e.g. a bottle of fresh refrigerant! This would cause error messages during the software test and the leak check! During the initial start-up the display will occasionally show Error Code 12, which means there is no refrigerant in the internal tank. Quit this error message by pressing the STOP button.
• Open the lid of the oil compartment on the left-hand side of the unit and hook all three oil bottles in place.
• There are two different sizes of oil bottles, 250 ml (open plastic containers) and 500 ml (professional oil system, closed metal containers). As the containers will be included in the weighing, it is important to set the right bottle size on the service unit. This is because the two differently sized containers have different empty weights and capacities. The factory setting is 250 ml. If you want to use large bottles, please use the arrow keys to go to “Other menus“ > press ENTER > then go down right to the bottom to “Service” > press ENTER > key in Code 2688, and select 500 ml. To get back to the basic menu press the STOP button several times.
• The pressure sensor should be calibrated, especially if the service station is used at a higher altitude above sea level where the atmospheric pressure is lower. To calibrate the sensor use the arrow keys to go to “Other menus” > press ENTER > then go down right to the bottom to “Service” > press ENTER > key in Code 2224, and follow the instructions on the display. For balancing the unit with the atmospheric pressure, the service couplers have to be unscrewed and removed from the hoses, so that you can look into the hoses.

The safety concept takes care that the service station can only be put into operation when is it closed all around and fresh air from the blower is flowing through it. This is why the front cover and the rear cover of the drier filter are fitted with contact switches, which are activated when the lids are opened. Simultaneously, the system monitors the blower speeds of the rear housing fan and the vacuum pump fan on the side of the unit. If the housing is being opened, or if one of the fans fails, the voltage supply to the unit is automatically interrupted, and an alarm sounds from the external box on the rear.

For safety reasons, the unit, after having been switched on, is flooded through with fresh air for 35 seconds before voltage is passed on to the system. Should a flammable mixture have formed anywhere in the housing – which may have, for example, been caused by a leak – this precaution makes sure the mixture won’t be ignited by an electric spark.

During the software test almost all possible operations of the unit are subjected to a test run. At the same time all components are preheated to get them to their ideal working temperature. This will, among other things, improve the charging and recovery accuracy of the machine. Additionally, the system performs a daily internal leak check whereby several components and connecting pipes are checked for tightness, first using vacuum, then with refrigerant. If pressure drops are detected in the process the unit won’t start operation.

Our A/C service units are supplied without refrigerant. Error Code 12 means that there is too little pressure (i.e. refrigerant) in the unit to perform the daily leak check and the subsequent software test. Please fill up the internal tank with refrigerant. To do this connect a bottle of fresh refrigerant (shake before use), select “Other menus” using the arrow keys and confirm with ENTER, then select “Int. bottle filling”, press the ENTER button and key in the desired quantity of refrigerant.
Note: The VAS6744A fills refrigerant by pressure difference. It is therefore technically impossible to charge 500 g of refrigerant into an A/C system if the service unit contains only 500 g of refrigerant. The more refrigerant is contained in the internal tank the faster and easier the charging process will go. We recommend a minimum quantity of 5 kg to be contained in the unit.

The VAS6744A fills refrigerant by pressure difference. It is therefore technically impossible to charge 500 g of refrigerant into an A/C system if the service unit contains only 500 g of refrigerant. The more refrigerant is contained in the internal tank the faster and easier the charging process will go. We recommend a minimum quantity of 5 kg to be contained in the unit.

The A/C systems have different connection ports. R134a service couplers won’t fit R1234yf service ports and vice versa. Likewise, it is impossible to connect an R134a service coupler to R1234yf service hoses, etc.

The VAS6744A features an integrated refrigerant analysis module, which checks the purity of the existing refrigerant prior to every recovery process. If the purity is below 95%, the service unit will refuse acceptance.

To prevent measuring errors the analysis can be repeated up to three times. If the analysis keeps reporting failure, the connected A/C system does not contain pure refrigerant. The refrigerant must be disposed of. For the purpose, the VAS6744A has a connection on the rear to which you can connect a separately available disposal system. Once the disposal is complete you can do a cross check by connecting a bottle of fresh refrigerant (shake before use) to the service station and repeat the original process. The analysis should read “OK” now.

According to the risk analysis of the German TÜV the service unit may only be used for charging A/C systems that have no leaks. To meet this requirement the A/C system is first put under vacuum (negative pressure) and checked for pressure changes for a certain period of time. Then a little amount of refrigerant is added to generate positive pressure, and the system is again monitored at a constant pressure level. If the pressure rises or falls in either of the two phases you will know that the A/C system leaks. In that case the service unit will interrupt the process and display an error message.
To guarantee accurate charging at all times it is then necessary to recover the pre-charged amount of refrigerant and completely evacuate the A/C system before. Once this has been done you can go ahead and charge the actually required amount of refrigerant.

The service units are set to English in the factory settings. To set another language simply use the arrow keys to go up/down to menu item “Other Selections” and confirm with ENTER to access the next menu. Then use the arrow keys to go down right to the bottom to “Service”, again confirm with ENTER and key in the code 5264. Arrived here you can select the desired language with the arrow keys and confirm with ENTER. By pressing the STOP button several times you get back to the basic menu.

Simply select your country to see the responsible Dometic WAECO Sales Company including the corresponding contact information.