45English17 3 Service mode operationRefrigerant recovery operation/vacuuming operation is possible byapplying setting [2-21]. Refer to 13.2. Operating the push buttons andDIP switches on the printed circuit board on page 24 for details howto set mode 2.When vacuuming/recovery mode is used, check very carefully whatshould be vacuumed/recovered before starting. See installation manualof the indoor unit for more information about vacuuming and recovery.17 3 1 Vacuuming method1 When the unit is at standstill, set the unit in [2-21]=1.2 When confirmed, the indoor units and outdoor unit expan-sion valves will fully open. At that moment the segment displayindication=t.01 and the user interface of all indoor units indicateTEST (test operation) and (external control) and the opera-tion will be prohibited.3 Evacuate the system with a vacuum pump.4 Press BS3 to stop vacuuming mode.17 3 2 Refrigerant recovery operation methodThis should be done by a refrigerant recovery equipment. Follow thesame procedure as for vacuuming method.18 Caution for refrigerant leaks18 1 IntroductionThe installer and system specialist shall secure safety againstleakage according to local regulations or standards The followingstandards may be applicable if local regulations are not availableThe VRV System, like other air conditioning systems, uses R410A asrefrigerant. R410A itself is an entirely safe non-toxic, non-combustiblerefrigerant. Nevertheless care must be taken to ensure that air con-ditioning facilities are installed in a room that is sufficiently large. Thisassures that the maximum concentration level of refrigerant gas is notexceeded, in the unlikely event of major leak in the system and this inaccordance to the local applicable regulations and standards.Maximum concentration levelThe maximum charge of refrigerant and the calculation of the maxi-mum concentration of refrigerant is directly related to the humanlyoccupied space in to which it could leak.The unit of measurement of the concentration is lbs./ft. 3 (kg/m 3 ) (theweight in lbs. (kg) of the refrigerant gas in 1 ft. 3 (1 m 3 ) volume of theoccupied space).Compliance to the local applicable regulations and standards for themaximum allowable concentration level is required.211 Direction of the refrigerant flow.2 Room where refrigerant leak has occurred (outflow of allthe refrigerant from the system).Pay special attention to places, such as basements etc , whererefrigerant could stay, since refrigerant is heavier than airProcedure for checking maximum concentrationCheck the maximum concentration level in accordance with steps 1 to2 below and take whatever action necessary to comply.1 Calculate the amount of refrigerant (lbs. (kg)) charged to eachsystem separately.Amount of refrigerantin a single unit system(amount of refrigerantwith which the systemis charged before leav-ing the factory)+Additional chargingamount (amount of re-frigerant added locallyin accordance with thelength or diameter ofthe refrigerant piping)= Total amountof refrigerant(lbs. (kg)) inthe systemNOTEWhere a single refrigerant facility is divided into 2 entirely independentrefrigerant systems then use the amount of refrigerant with whicheach separate system is charged.2 Follow local code requirements (ASHRAE-15 2007 & ASHRAE-342007).19 Disposal requirementsDismantling of the unit, treatment of the refrigerant, of oil and of otherparts must be done in accordance with relevant local and nationallegislation.