Honeywell ST 3000 User Manual page 186

9.3 Inspecting and Cleaning Barrier Diaphragms,
Procedure, continued
172 ST 3000 Release 300 and SFC Model STS103 User's Manual
Table 53 Inspecting and Cleaning Barrier Diaphragms, continued
Step
Remove O-ring and clean interior of process head using soft bristle
3
brush and suitable solvent.
4 Inspect barrier diaphragm for any signs of deterioration or corrosion.
Look for possible residue and clean if necessary.
NOTE: If diaphragm is dented, has distorted convolutions or radial
wrinkles, performance may be affected. Contact TAC for
assistance.
5 Replace O-ring.
ATTENTION
• We recommend that you install a new O-ring whenever a process
head is removed for cleaning.
• The process head for a GP or an AP transmitter with single-head
design has two O-ring grooves. A large one which is 2 in (50.8
mm) in diameter and a small one which is 1.3 in (33 mm) in
diameter as shown in the following illustration. On high-pressure,
model STG180, GP transmitters, be sure to use a small O-ring in
the smaller/inner groove. On other models of GP and AP
transmitters, use a large O-ring in the larger/outer groove. Never
use both O-rings together.
Larger O-ring
groove for
lower pressure
applications
• For process heads of a GP or AP transmitter with dual-head
design, see detail illustration for differential pressure transmitters
in Step 2.
Action
Smaller O-ring
groove for
high pressure
applications
GP/AP Process Head
Continued
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