Yokogawa EJA220A - Manual (Page 55)

IM 01C21C01-01E 9-5
9. MAINTENANCE
NOTE
Confirm that the zero-adjustment screw pin is
placed properly in the groove on the bracket
prior to tightening the two bosses. If it is not, the
zero-adjustment mechanism will be damaged.
5) Replace the cover.
9.4.3 Replacing the Process Connector
Gasket
This subsection describes the procedure for replacing
the process connector gasket. (See Figure 9.4.3.)
1) Loosen the two bolts and remove the process
connector.
2) Replace the process connector gasket.
3) Mount the process connector. Tighten the bolts
securely and uniformly to a torque of 39 to 49 N·m
{4 to 5 kgf·m}, and verify that there are no pressure
leaks.
Process connector
gasket
Process connector
Bolt
F0904.EPS
Figure 9.4.3 Replacing the Process Connector Gasket
9.5 Troubleshooting
If any abnormality appears in the measured values, use
the troubleshooting flow chart below to isolate and
remedy the problem. Since some problems have
complex causes, these flow charts may not identify all.
If you have difficulty isolating or correcting a problem,
contact Yokogawa service personnel.
9.5.1 Basic Troubleshooting
First determine whether the process variable is actually
abnormal or a problem exists in the measurement
system.
If the problem is in the measurement system, isolate
the problem and decide what corrective action to take.
This transmitter is equipped with a self-diagnostic
function which will be useful in troubleshooting; see
Section 8.5 for information on using this function.
Abnormalities appear in measurement.
: Areas where self-diagnostic offers support
Is process variable
itself abnormal?
Inspect the
process system.
Isolate problem in
measurement system.
Does problem exist in
receiving instrument?
Check/correct
environmental conditions.
Inspect receiver.
Check transmitter.
Check/correct operating
conditions.
Measurement system problem
F0905.EPS
YES
NO
NO
YES
Environmental conditions
Operating conditions
Transmitter itself
Figure 9.5.1 Basic Flow and Self-Diagnostics