Mitsubishi Electric PUHY-M200YNW-A1 Service Handbook page 343

[8-13 Parts Replacement Instructions ]
(3) Remove the pipe cover and thermal insulation adjacent to the four-way valves. (See Figure 4.)
Figure 4
*Notes on replacing refrigerant circuit components (check valve, four-way valve, solenoid valve, and LEV)
Be sure to perform non-oxidized brazing.
Before heating the pipes, wrap the refrigerant circuit components with a wet towel to keep the temperature of the
components from rising above 120°C.
After brazing is done, check that the brazing is done properly and check for leaks before vacuum-drying the pipes.
Direct the brazing torch flame away from the wiring and sheet metals inside the unit not to damage them.
Wet felt sheets listed below (or its equivalent), and place them around the areas to be brazed to protect the heat
exchanger, pipes, and pipe covers from being damaged from the brazing torch flame.
Recommended felt sheets: Spatter felt 50CF-11 (5t x 1 m x 1 m) by TRUSCO Nakayama
Felt sheets that meet the JIS standard (JIS A 1323 type A "Flame retardant testing method for spark droplets of
welding and gas cutting on fabric sheets in construction works")
(4) Remove the braze from the pipe between four-way valves (21S4a and 21S4b). (See Figure 5.)
Figure 5
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Remove the pipe cover adjacent to four-way valves.
*Save the pipe cover for later use.
Cut the cable tie here.
Cut the cable tie here.
BS_08_E