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200/202 Series Flowmeters and Controllers Instruction Manual
3.3.2.
Miscellaneous Adjustments
Periodically, during normal operation, the ZERO should be checked and adjusted when required. If the
instrument is not shutting completely off when the Valve Override CLOSE function is active, or a
command of zero flow has been given, the orifice may require approximately 1/8 turn clockwise.
Endcap Removal
The endcap on the inlet side must be removed to gain access to the filter or shunt assembly. First shut
off the supply of gas to the instrument. Disconnect the Swagelok fittings on the inlet and outlet sides of
the unit and remove it from the system plumbing. Remove the four hex bolts holding the endcap to the
instrument. Carefully remove the endcap, filter, wave spring (if present) and shunt, noting their order and
proper orientation. The shunt can be severely damaged if dropped. Examine the filter and shunt. If either is
dirty or blocked, clean or replace as applicable. Reassembly is the reverse of the removal procedure.
Recalibration of the HFC is necessary.
Printed Circuit Board Replacement
In the unlikely event that the PC board fails, it is easily removed from the instrument and replaced with a
spare to minimize instrument downtime. Replacement of the PC board will require the instrument to be
recalibrated. Unplug the power cable from the top of the transducer. Remove the two jackscrews next to the
"D" connector and the two screws on the sides of the cover. Lift off the cover and unplug the four-wire sensor
plug and the two-wire valve plug, noting their orientation prior to removal. Remove the screw that holds the
PC board to the sensor. Troubleshoot or replace as applicable. Installation is the reverse of the above
procedure. Recalibrate if any components were changed or if any potentiometers were adjusted.
Sensor Replacement
If the sensor fails or becomes plugged it can be removed. Remove the cover and the PC board per Section 3.5
above. Remove the three bolts holding the sensor to the instrument base. Remove the sensor from the base
noting the two O-rings between the sensor and the base. If the sensor is plugged it can be cleaned by running a
fine wire (approximately 0.008" diameter) through the tube. If sensor needs replacement, obtain another from
the factory and install it. Ensure that O-rings are clean and intact. Install O-rings on seating surface, then
carefully place sensor over O-rings and tighten down the three screws evenly. Replacement of sensor will
require recalibration per Section 3.3.1.
Orifice Changes
The orifice may require replacement if a large flow range
change is desired, if changing to a gas that has a specific
gravity significantly different than the original gas, if a large
change in the differential pressures across the valve is
desired or in the event that a small orifice becomes plugged.
Replacement orifices can be acquired from the factory.
Orifice diameters (inches) available are 0.001, 0.002, 0.003,
0.007, 0.014, 0.020, 0.032, 0.042, 0.052, 0.062, and 0.070.
Contact the factory to order new orifice.
EAR99 Technology Subject to Restrictions Contained on the Cover Page
Page 23 of 27
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