2. The PTFE gasket may be re-used if free from fault, crush or deformation.
3. Apply anti-seize to the threaded portion of screws and bolts, the spring retainer, ball and
adjustment screw. Apply a small amount of anti-seize to the threads of the main valve seat,
pilot valve seat and pilot screen holder. Apply anti-seize carefully to ensure it does not come
into contact with other parts.
4. Fasten the bolts one at a time in an alternating diagonal pattern to provide uniform seating.
5. After assembly, make sure that the piston and the pilot valve operate smoothly without
binding.
Assembling the Piston Ring
Ring Gaps
6.9 Regular Inspection and Maintenance
To ensure long service life, the following inspection and maintenance should be done regularly.
Part
Separator Screen (COS only),
Pilot Screen
Main Valve, Main Valve Seat,
Pilot Valve and Pilot
Valve Seat
Piston Ring
Piston
Trap Valve Seat
Diaphragm
1) Fit the piston ring to the outside of the tension ring.
2) The ring gaps should be opposite each other.
Piston Ring
Tension Ring
Inspection and Maintenance Frequency
Disassemble and clean annually.
If there is substantial blockage, install a strainer (approx.
60 mesh) ahead of the COS/COSR.
Replace after 15,000 hours.
If there is chattering or dirt, premature wear may result.
Replace after 8,000 hours.
If there is chattering or if scale build-up is severe, premature
wear may result.
Replace after 30,000 hours.
If hunting or chattering takes place, premature wear may
result.
Replace after 40,000 hours.
If scale build-up is severe, blockage may occur in a short
period of time.
Replace after 30,000 hours.
If hunting or chattering takes place, cracks or fatigue may
develop in a short period of time.
̶ 22 ̶