168-082010_ 210-212 Meter/Controller Page 16 of 17
4.4. Fitting and Shunt Changes:
It is possible to change the fittings or the shunt, if necessary, as long as the instrument is recalibrated. These
changes should be made with the instrument removed from all electrical and mechanical connections. The
fitting on the downstream side of the instrument can be changed without needing recalibration. The upstream
fitting is modified, however, and removing it will void the calibration. To remove or replace the shunt,
carefully remove the inlet fitting, retaining spring (if present) and the 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.
4.5. 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
per Section 4.3.1.
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.
4.6. Sensor Replacement:
If the sensor fails or becomes plugged it can be removed. Remove the cover and the PC board per Section 4.5
above. Remove the three bolts holding the sensor to the instrument base. Remove the sensor from the base
noting the two O-rings (Parker 2-005, V884-75) 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 4.3.1.
4.7. Orifice Changes:
The orifice may require replacement if a flow range change is desired, if a large change in 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 having a Cv in the range of 0.0000263 to 0.129.
To change the orifice in the HFC-212 series, turn the instrument upside-down and turn the orifice
counterclockwise with a 9/64" Allen wrench until it stops coming out. Then grasp the exposed orifice end and
pull it straight out. See Figure 4.2.
Prior to reinstallation of the orifice, inspect the two
O-rings mounted on it for damage. Replace if cut or
gouged.
Lubricate the O-rings slightly with a silicone based
grease, and the threads with anti-galling compound.
Push the orifice into its hole and screw it in until it is
flush with the instrument base. Apply pressure to the
inlet side of the instrument.
Turn the Valve Override switch to CLOSE or unplug
the instrument. Screw the orifice in a few more turns
until the flow through the instrument stops, then turn
it an additional 1/4 turn clockwise.
