Kenco Engineering KDV DumpValve - Manual (Page 4)

DIAPHRAGM AND TRIM SHAFT REPLACEMENT
1. Remove the trim plug and seat following steps 1 through 9 under Trim Seal Repair Procedure.
2. Remove the maintenance bolt (#10), nut (#11), flat washer (#12) and seal washer (#13). This will
take most of the load off of the valve spring, making the next step easier. (See Figure 3)
Figure 3
3. Make an alignment mark on the housing halves (#16, #19) and remove the eight ¼ “ nuts (#15)
and bolts (#14). The valve spring (#18) will probably force the 2 housing halves apart, but if not,
gently pry the halves apart with a flat tip screwdriver. Take care not to gouge the sealing surface
of the housings.
4. With the two halves apart, remove the old diaphragm assembly (#17).
5. If the valve is a 2” model, slide the washer (#26) on the shaft. Make sure the flat side of the
washer sits on the shoulder of the shaft and that the proper end of the shaft is selected.
6. Install the new thrust plate (#23) with the edge of the rolled lip facing the body side of the
housing (#19) Use the old assembly for reference if necessary. Also install the diaphragm (#22),
washer (#21) and nut (#20). If the valve is a 2” model, the washer (#21) will have a counter bore
on one side. This counter bore must face the diaphragm (#22). Failure to orient this washer
properly will result in leakage and early valve failure. This only applies to the 2” KDV’s.
7. Use a 1-1/8” wrench to back up the hex end of the trim shaft (#24) and tighten the nut (#20) to
220 in lbs (1”KDV) or 180 in lbs (2” KDV) or until it slightly compresses the surface of the
diaphragm (#22).
8. Remove the o-ring (#25) and insert the new o-ring into the groove in the spud (#9 in figure 2).
Use plenty of o-ring lubricant.
9. Smear a thin coat of O-ring lube on the shaft (#24) near the end with the hex. This will help
lubricate the o-ring and packing and will improve the life of these seals.
10. Insert the shaft into the spud on the housing (#19). If the valve is a 2” valve, the shaft will have a
fairly sharp edge on the shoulder the trim plug (#4 figure 3) bolts up against. Use care when
inserting the shaft. The shaft should be gently rotated while applying some pressure to push it
past the O-ring (#25). If caution is not used here, the O-ring (#25) and or packing (#26 figure 2)
could be damaged.
11. It is easiest to install the packing (#26 figure 2) after the diaphragm assembly is completed.
Simply lube the packing thoroughly and work it gently over the trim shaft. Make sure it is
oriented properly. The narrow end will sit in the bottom of the groove and the wide end should
face the trim plug. Warning! If this seal is put in backwards, the valve will leak fluid and/or gas
out of the weep hole. Use the trim seat (#6 Figure 2) to fully seat the packing in the groove.
12. Assemble the rest of the valve following steps 10 through 13 under Trim Seal Repair Procedure.