VERDER VERDERAIR VA 25 Instructions-Parts List Manual page 18

Service
4. Loosen but do not remove the diaphragm shaft
bolts (107), using a 15 mm socket wrench (1 in. on stain-
less steel models) on both bolts.
5. Unscrew one bolt from the diaphragm shaft (24) and
remove the o-ring (108), fluid side diaphragm plate (105),
PTFE diaphragm (403, used on PTFE models only), dia-
phragm (401), and air side diaphragm plate (104). See
Fig. 14.
6. Pull the other diaphragm assembly and the diaphragm
shaft (24) out of the center housing (1). Hold the shaft
flats with a 19 mm open–end wrench, and remove the
bolt (107) from the shaft. Disassemble the remaining
diaphragm assembly.
7. Inspect the diaphragm shaft (24) for wear or scratches. If
it is damaged, inspect the bearings (19) in place. If the
bearings are damaged, refer to page 20.
8. Reach into the center housing (1) with an o-ring pick and
hook the u-cup packings (402), then pull them out of the
housing. This can be done with the bearings (19) in
place.
9. Clean all parts and inspect for wear or damage. Replace
parts as needed.
Reassembly
1. Install the shaft u-cup packings (402*) so the lips face
out of the housing (1). Lubricate the packings. See
Fig. 14.
2. Install the diaphragm assembly on one end of the
shaft (24) as follows:
a. Install the o-ring (108*) on the shaft bolt (107).
b. Install the fluid side diaphragm plate (105) on the
bolt so the rounded side faces the diaphragm (401).
18 819.4470
NOTE: On stainless steel pumps only, the fluid side dia-
phragm plate (105) is stainless steel. This plate is
not stamped with its part number. Be sure to install
this plate on the fluid side of the diaphragm.
c. On PTFE models only, install the PTFE dia-
phragm (403*). Make certain the side marked AIR
SIDE faces the center housing (1).
d. Install the diaphragm (401*) on the bolt. Make cer-
tain the side marked AIR SIDE faces the center
housing (1).
e. Install the air side diaphragm plate (104) so the
rounded side faces the diaphragm (401). This plate
is used on all models, and is stamped with its part
number.
f. Apply medium-strength (blue) LoctiteR or equivalent
to the bolt (107) threads. Screw the bolt into the
shaft (24) handtight.
3. Grease the length and ends of the diaphragm shaft (24),
and slide it through the housing (1).
4. Assemble the other diaphragm assembly to the shaft as
explained in step 2.
5. Hold one shaft bolt (107) with a wrench and torque the
other bolt to 27–34 NSm at 100 rpm maximum.
6. Align the fluid covers (101) and the center housing (1) so
the arrows (A) on the covers face the same direction as
the air valve (B). Secure the covers with the
screws (106), handtight. See Fig. 13. Using a 10 mm
socket wrench, torque the screws oppositely and evenly
to 14–17 NSm. See Torque Sequence, page 28.
7. Reassemble the ball check valves and manifolds as ex-
plained on page 16.