Toshiba R410A Service Manual page 7

• 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 Refrigerant
The pressure of R410A is high 1.6 times of that of the former refrigerant (R22). Accompanied with change of
refrigerant, the refrigerating oil has been also changed. Therefore, be sure that water, dust, the former refriger-
ant or the former refrigerating oil is not mixed into the refrigerating cycle of the air conditioner with new refriger-
ant during installation work or service work. If an incorrect work or incorrect service is performed, there is a
possibility to 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
former refrigerant 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 are
specified for R410A.
(3) In the installation time, use clean pipe materials and work with great attention so that water and others do
not mix 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 condi-
tioner change.)
3. Pipe Materials
For the refrigerant pipes, copper pipe and joints are mainly used. It is necessary to select the most appropriate
pipes to conform to the standard. Use clean material in which impurities adhere inside of pipe or joint to a
minimum.
(1) Copper pipe
<Piping>
The 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 without
seam" 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.)
<Flare nut>
Use the flare nuts which are attached to the air conditioner unit.
(2) Joint
The flare joint and socket joint are used for joints of the copper pipe. The joints are rarely used for installa-
tion of the air conditioner. However clear impurities when using them.
4. Tools
(1) Required Tools for R410A
Mixing of different types of oil may cause generation of sludge, clogging of capillary, etc.
Accordingly, the tools to be used are classified into the following three types.
1) Tools exclusive for R410A (Those which cannot be used for conventional refrigerant (R22))
2) Tools exclusive for R410A, but can be also used for conventional refrigerant (R22)
3) Tools commonly used for R410A and for conventional refrigerant (R22)
The table below shows the tools exclusive for R410A and their interchangeability.
Tools exclusive for R410A (The following tools for R410A are required.)
Tools whose specifications are changed for R410A and their interchangeability
No. Used tool Usage
Flare tool Pipe flaring
Copper pipe gauge for
Flaring by conventional
adjusting projection
flare tool
margin
Torque wrench Connection of flare nut
Gauge manifold
Evacuating, refrigerant
charge, run check, etc.
Charge hose
Vacuum pump adapter Vacuum evacuating
Electronic balance for
Refrigerant charge
refrigerant charging
Refrigerant cylinder Refrigerant charge
Leakage detector Gas leakage check
Charging cylinder Refrigerant charge
(Note 1) When flaring is carried out for R410A using the conventional flare tools, adjustment of projection
margin is necessary. For this adjustment, a copper pipe gauge, etc. are necessary.
(Note 2) Charging cylinder for R410A is being currently developed.
General tools (Conventional tools can be used.)
In addition to the above exclusive tools, the following equipments which serve also for R22 are necessary
as the general tools.
(1) Vacuum pump
Use vacuum pump by
attaching vacuum pump adapter.
(2) Torque wrench
(3) Pipe cutter
(4) Reamer
(5) Pipe bender
(6) Level vial
Also prepare the following equipments for other installation method and run check.
(1) Clamp meter
(2) Thermometer
R410A Conventional air
air conditioner installation conditioner installation
Existence of Whether conven- Whether new equipment
new equipment tional equipment can can be used with
for R410A be used conventional refrigerant
Yes *(Note 1) Yes
Yes *(Note 1) *(Note 1)
Yes No No
Yes No No
Yes No Yes
Yes Yes Yes
Yes No No
Yes No Yes
(Note 2) No No
(7) Screwdriver (+, –)
(8) Spanner or Monkey wrench
(9) Hole core drill
(10) Hexagon wrench (Opposite side 4mm)
(11) Tape measure
(12) Metal saw
(3) Insulation resistance tester (Megger)
(4) Electroscope (Volt meter)