Mitsubishi Electric EHPT20Q-VM2EA Service Manual page 74

From the previous page.
DISASSEMBLY PROCEDURE
15. How to remove the HEX(Primary and Sanitary
circuit)
< HEX >
(1) Remove the front panel.
(2) Stop water flow at the water source.
(3) Open the pressure relief valve cap and lower the
tank internal pressure.(Photo 12-5)
(4) Drain water inside the HEX using the drain cock
(Primary circuit) and the drain cock (Sanitary
circuit). (Photo 13-4)
(5) Detach 4 quick connections.(Photo 15-1)
(6) Remove the 2 screws to remove the cover.
(Photo 15-2 and 15-3)
(7) Remove the HEX and drain cock (Sanitary
circuit).
and O-ring, use a new one.
Photo 15-2
GCH15010
HEX
screw
cover
PHOTOS
Photo 15-1
HEX
2 quick
connections
Photo 15-3
74
2 quick
connections
HEX
screw
cover