Panasonic U-72MF2U9 Service Manual page 92

9. Compressor
9. Compressor
(13) If the results show that dry core cleaning is still necessary (for example, a color phase of 4.0 or higher)*,
return to Step (11) and repeat until the results are normal (including a color phase of 3.5 or less)*.
* Color sample sheet for degree of stain
CAUTION
(14) Perform steps (1) – (4), and remove all dry cores. Then connect the tube between the liquid tube valves and
the ball valves.
(15) At all outdoor units where dry cores were removed, pressurize with 484 psi (3.34MPa) of nitrogen from the
liquid tube service port and check for leaks.
(16) After evacuating all nitrogen gas from the tube, apply vacuum to all outdoor units where dry cores were
removed until the pressure is –14.7 psig {-101kPa, 5 Torr} or less.
1
(17) INSTALLATION: Refer to the Installation Instructions for further information.
(B) If a ball valve is not installed on the outdoor unit
2
(1) See "4-2-3. Refrigerant recovery procedures (2) : Indoor unit with no ball valve equipped". Perform pump
down of the refrigerant from all indoor units and inter-unit tube to the outdoor unit side.
(2) Cut the liquid tube at all outdoor units where dry cores will be attached, then attach the dry cores and ball
valves as shown in Fig. 16.
3
(3) For the next steps, see the steps (6) – (17) in "(A) If a ball valve is installed on the outdoor unit" on the
previous page.
4
5
6
7
8
9
Perform another dry core replacement after approximately 30 hours of system operation.
Charge with an amount of refrigerant equal to the amount that was recovered.
Outdoor unit for
cleaning by dry core
Dry core (bidirectional: for R410A refrigerant)
Outdoor Unit Repair Procedures
Outdoor Unit Repair Procedures
Normal outdoor unit
Suction tube
Liquid tube
Discharge tube
Balance tube
Ball valve
2 - 28
2WAY VRF SYSTEM
3WAY VRF SYSTEM
Liquid tube service port
(for ø5/16" (ø7.94mm)-
dia connector)
To indoor unit
Fig. 16