Hitachi UTOPIA RAS-3HVRC2 Manuel D'utilisation page 29

REFRIGERANT PIPING & REFRIGERANT CHARGE
8.2.1 Outdoor unit stop valve
Operation of stop valve should be performed according to the
figures and tables below:
Spindle Type
 Spindle valve
 Flare nut
 Cap
  C heck joint for service port
Tightening Torque (Nm)
 
Gas Liquid Gas Liquid
valve valve valve valve
9-11 7-9 68-82 34-42
Spindle valve
Tighten the spindle with a torque above:
Counterclockwise.... Open
Clockwise ............... Close
Closed before shipment
Check joint
(Only charging hose can
be connected)
Tighten the cap with 16 Nm torque
Cap
Tighten the cap with 37 Nm torque
(Attach this after work)
8.3 BRAZING WORK
!
C A U T I O N
• Use nitrogen gas for blowing during pipe brazing. If oxygen,
acetylene or fluorocarbon gas is used, it will cause an
explosion or poisonous gas.
• A lot of oxidation film will occur inside of tubes if no nitrogen
gas blowing is performed during brazing work. This film will
be flecked off after operation and will circulate in the cycle,
resulting in clogged expansion valves, etc. This will cause
bad influence to the compressor.
9 PMML0548 rev.0 - 04/2020 - A10648790A
Stop valve (liquid)
Stop
valve
(gas)
Closed upon factory shipping
 
Gas Liquid Gas Liquid
valve valve valve valve
33-42 33-42 14-18 14-18
Refrigerant pressure
Refrigerant piping
Hexagonal wrench
(field supplied) (*)
Hexagonal wrench size used for spindle valve:
(*) Size
Gas valve
Liquid valve
Do not apply two
spanners at this
position. If applied,
leakage will occur
Do not work with two
spanners here.
Refrigerant leakage
shall occur
Use two spanners here
for pipe connection
!
C A U T I O N
• At the test run, fully open the spindle and ball stop valve.
• If not fully opened, the devices will be damaged.
• Do not attempt to turn service valve rod beyond its stop.
• Do not loosen the stop ring. If the stop ring is loosened, it is dangerous
since the spindle will hop out.
• An excess or a shortage of refrigerant is the main cause of trouble
to the units. Charge the correct refrigerant quantity according to the
description of label at the inside of service cover.
• Check for refrigerant leakage in detail. If a large refrigerant leakage
occurs, it will cause difficulty with breathing or harmful gases would
occur if a fire was being used in the room.
• Use a reducer valve when nitrogen gas blowing is performed
during brazing. The gas pressure should be maintained
within 0.03 to 0.05MPa. If a excessively high pressure is
applied to a pipe, it will cause an explosion.
3HP
5 mm
4 mm
Stop valve
(Spindle type)
Flare nut