Spirax Sarco 37D, Installation And Maintenance Instructions Manual

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IM-P102-04 CTLS Issue 7
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To renew or clean the main diaphragms
Isolate the valve and zero the pressure. If the plant
is still in operation through a bypass valve or if the
medium surrounding the bulb is hot, withdraw the
sensor bulb and allow it to cool down, otherwise the
control system may be strained.
26. Undo the long union nut and pull away.
27. Undo the M12 nuts and bolts.
28. Drop away the lower diaphragm chamber, the
two diaphragms, diaphragm plate and push
rod assembly.
29. Thoroughly clean the lower diaphragm chamber
making sure the contact faces are clean.
30. Replace the diaphragm plate and push rod
assembly and loosely fit the lower diaphragm
chamber on two bolts either side of the union
connection to locate spigot in recess.
31. Bring the two new diaphragms together (where
precoated sealant is applied this should face
outwards) and slide into position. If diaphragms
are not renewed, but cleaned only care must
be taken to replace diaphragms in the original
order.
32. Push the lower diaphragm chamber home to
locate in the recess and refit M12 nuts and
bolts. Progressively and evenly tighten to a
torque of 80 - 100 N m (59 - 74 lbf ft).
33. Retighten the long union nut to ensure a steam
tight seal. Bring the valve back into commission
by following as many steps as are necessary
in Section 3.
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