Shortly after the piston valve is first put into service, the cover nuts should be lightly tightened with the valve in closed position, which in-turn compresses the valve packing ring firmly around the position.

When a leak develops it is easy to correct it with an ordinary spanner.

• Shut the valve fully.
• Tighten each cover nuts 1/8th of a turn.
• If the leak is slight and has not persisted for any length of time, this will be found sufficient, If not, then repeat the process until the valve is steam tight.

It is important to follow instruction no.1, If the cover nuts are tighten down with the valve open then the bottom ring may be compressed in the passage and get damaged by the Piston when the valve is again closed.

No undue force should be used in tightening the piston valve nuts. They should move easily with a standard spanner of the corresponding size & should be tightened equally to avoid tilting of the cover. Please do not use a wheel spanner on the hand wheel since there is no use of any undue force to shut the piston valve, it may simply damage the spindle.

Life of the rings depends on the above process as & when required until the rings are worn out & needs replacement.

To remove old sealing rings use a tang of an old file or screwdriver bent at right angle to form a hook, now pull out the top ring, lantern bush & the bottom ring one after another.

Replacing new piston & sealing rings is a simple matter, as they are provided with a machined Horseshoe slot. In some cases the piston are fitted by means of a split washer and nut.

• All nuts have left hand threads.
• The pistons are accurately machined & carefully finished, if it is necessary to hold the piston while fitting then grip it between a soft wooden clamp to avoid damaging the surface.
• Open the valve wide.
• Remove the cover nuts.
• Screw down the spindle (turn right) to lift the cover off the studs.
• Turn the cover so that it rests on top of the studs.
• Screw spindle up (turn Left) to withdraw piston from rings.
• Lift off cover parts, taking care to avoid scratching the piston.
• Use only genuine WOODLAND valve rings.
• Insert a new ring & drive it gently home using a punch / a short bar metals or wood having a slight small diameter than that of the ring. Tap the punch with the hammer lightly & drive the ring till the bottom of the bore.
• Replace the lantern bush, which should enter the bottom bore & sit flat on the ring.
• Insert the top ring by the same way as the bottom.

Replacing the valve cover

• See that the piston is in good condition, enter the piston through the passage between the rings and replace the cover.
• Screw down the cover nuts lightly, then screw down the hand wheel (turn right) then unscrew (Turn left) drawing the cover into position.
• Run the nuts down, shut the valve & tighten with spanner evenly just enough to grip the rings.
• Make sure that the cover is sitting square on the valve body.

Remember when the piston valve is first put under service, the cover nuts should be tightened lightly and evenly with the valve in closed position, this will enable to settle the rings firmly around the piston. This will increase the life of the rings & failure to this may result in premature leakage. Also note that the cover nuts should not be tighten without the Belleville washers.