Maintenance; Troubleshooting - Siemens 66 Series Installation And Service Instruction

SD66

MAINTENANCE

Most problems associated with pneumatic instruments can be prevented by providing clean, dry, oil-free instrument
air (see Instrument Air Requirements). If these requirements are met, routine maintenance should not be necessary.
Cleaning of the plunger and the supply and exhaust ports may be required, on an occasional basis, as outlined in the
Cleaning section.
Before disassembling the instrument, turn off supply air pressure to the instrument.

Troubleshooting

Table 1 provides troubleshooting information in a symptom, cause, and remedy format. Symptoms are listed in the
order they are most likely to occur.
SYMPTOM
Output pressure will not
decrease or decreases with a
decrease in input pressure.
Output pressure will not
increase or increases with an
increase in input pressure.
Excessive exhaust from
exhaust vent.
Cleaning
To clean the plunger and the supply and exhaust ports:
1. Remove supply and input pressures.
2. Remove the retaining nut from the bottom forging (see Parts List). The plunger and plunger spring should fall
out.
3. Clean the plunger with non-abrasive solvent.
4. Clean the supply and exhaust ports with non-abrasive solvent (see Figure 2). The supply port is readily
accessible; the exhaust port can be reached with a tobacco pipe cleaner.
If there is excessive buildup on the supply or exhaust port, the relay must be
disassembled for thorough cleaning. Refer to the Parts List for parts orientation during
disassembly and assembly.
5. Refer to the Parts List and install the plunger, plunger spring, and retaining nut.
6. Check the calibration of the Relay per the following Calibration.
Downloaded from StockCheck.com
CAUTION
Table 1 Troubleshooting
CAUSE
Plunger is not seating properly in
supply port due to dirt, chips, etc.
Exhaust port is clogged due to build up
on the plunger and/or exhaust port.
Exhaust port is obstructed.
Plunger is not seating properly in
exhaust port due to dirt, chips, etc.
Supply port is clogged due to build up
on the plunger and/or supply port.
Supply pressure is too low.
Ruptured input diaphragm or output
diaphragm assembly.
Plunger is not seating properly in
exhaust port due to dirt, chips, etc.
NOTE
4
REMEDY
Refer to Maintenance, Cleaning and clean
plunger and supply port.
Refer to Maintenance, Cleaning and clean
plunger and exhaust port.
Clear obstruction.
Refer to Maintenance, Cleaning and clean
plunger and exhaust port.
Refer to Maintenance, Cleaning and clean
plunger and supply port.
Raise supply pressure.
Refer to Maintenance to replace input
diaphragm or output diaphragm assembly.
Refer to Maintenance, Cleaning and clean
plunger and exhaust port.