Assembling The Head - Valve Units - Pratissoli MK Serie Manuel De Réparation

2.2.2 Assembling the head – valve units
Pay particular attention to the conditions of the
various components and replace if necessary.
At every valve inspection, replace all O-rings
both in the valve unit and in the valve plugs.
Before repositioning the valve units, thoroughly
clean and dry the relative housings on the head
indicated by the arrows (pos. , Fig. 88).
Proceed with reassembly following the reverse order indicated
in par. 2.2.1.
Assemble the suction and outlet valve units (Fig. 89 and
Fig. 90) taking care not to invert the previously disassembled
springs.
To facilitate insertion of the valve guide in its housing, you can
use a pipe resting on the horizontal guide planes (Fig. 91) and
use an extractor hammer acting on the whole circumference
The proper sequence of valve unit assembly on the head is as
follows:
Insert the anti-extrusion ring, exploded view pos. 4 (pos. ,
Fig. 92).
Fig. 88
Insert the O-ring, exploded view pos. 5 (pos. , Fig. 93).
Fig. 89
Ensure that the O-ring and anti-extrusion ring are perfectly
placed in their housings.
Fig. 90
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Proceed with insertion of the valve units (suction
and outlet) in the head, taking care to follow the
correct insertion sequence of O-rings and anti-
extrusion rings.
Fig. 91
Fig. 92
Fig. 93