SERVICE MANUAL - Toshiba

New Refrigerant (R410A)This air conditioner adopts a new HFC type refrigerant (R410A) which does not deplete the ozone layer.1. Safety Caution Concerned to New RefrigerantThe pressure of R410A is high 1.6 times of that of the former refrigerant (R22). Accompanied with change ofrefrigerant, the refrigerating oil has been also changed. Therefore, be sure that water, dust, the former refrigerantor the former refrigerating oil is not mixed into the refrigerating cycle of the air conditioner with new refrigerantduring installation work or service work. If an incorrect work or incorrect service is performed, there is a possibilityto cause a serious accident. Use the tools and materials exclusive to R410A to purpose a safe work.2. Cautions on Installation/Service(1) Do not mix the other refrigerant or refrigerating oil.For the tools exclusive to R410A, shapes of all the joints including the service port differ from those of the formerrefrigerant in order to prevent mixture of them.(2) As the use pressure of the new refrigerant is high, use material thickness of the pipe and tools which arespecified for R410A.(3) In the installation time, use clean pipe materials and work with great attention so that water and others do notmix in because pipes are affected by impurities such as water, oxide scales, oil, etc. Use the clean pipes.Be sure to brazing with flowing nitrogen gas. (Never use gas other than nitrogen gas.)(4) For the earth protection, use a vacuum pump for air purge.(5) R410A refrigerant is azeotropic mixture type refrigerant. Therefore use liquid type to charge the refrigerant.(If using gas for charging, composition of the refrigerant changes and then characteristics of the air conditionerchange.)3. Pipe MaterialsFor the refrigerant pipes, copper pipe and joints are mainly used. It is necessary to select the most appropriatepipes to conform to the standard. Use clean material in which impurities adhere inside of pipe or joint to a minimum.(1) Copper pipeThe pipe thickness, flare finishing size, flare nut and others differ according to a refrigerant type.When using a long copper pipe for R410A, it is recommended to select “Copper or copper-base pipe withoutseam” and one with bonded oil amount 40mg/10m or less. Also do not use crushed, deformed, discolored(especially inside) pipes. (Impurities cause clogging of expansion valves and capillary tubes.)Use the flare nuts which are attached to the air conditioner unit.(2) JointThe flare joint and socket joint are used for joints of the copper pipe. The joints are rarely used for installationof the air conditioner. However clear impurities when using them.21