Dwyer GFC - Manual (Page 24)

7.3.6 75% Flow Adjustment
Using the flow regulator, increase the flow rate to 75% of full scale flow. Check the
flow rate indicated against the flow calibrator. The output of the flow meter should
read 3.75VDC ±63mV (or 16mA ±0.25mA). If the reading is outside of that range,
place the jumper at [J1B] as appropriate to increase or decrease the signal. Adjust
the setting for potentiometer [R39] by using the insulated screwdriver through the
access window, until reading is within specification.
7.3.7 100% Flow Adjustment
Using the flow regulator, increase the flow rate to 100% of full scale flow. Check
the flow rate indicated against the flow calibrator. The output of the flow meter
should read 5.00VDC ±63mV (or 20mA ±0.25mA). If the reading is outside of that
range, place the jumper at [J1C] as appropriate to increase or decrease the sig-
nal. Adjust the setting for potentiometer [R40] by using the insulated screwdriver
through the access window, until reading is within specification.
Repeat steps 7.3.4 to 7.3.7 at least once more.
7.3.8.1 Valve Adjustment for GFC-110/111/113/114
Discontinue the PURGE mode (set valve for the closed position). Apply an inlet
pressure of 5 psig, and atmospheric pressure at the outlet. If a small flow occurs,
turn the set screw on top of the solenoid valve clockwise until the flow through the
GFC just stops
7.3.8.2 Valve Adjustment for GFC-1143/1144/1145
DO NOT adjust the motorized valve for GFC-1143/1144/1145.
The motorized valve for these models has been pre-adjusted at the factory.
7.3.9 Full Scale Flow Adjustment
Fully open the flow regulator upstream of the GFC. Increase the inlet pressure to
20 psig (25 psig for GFC-1145). Apply a +5.00 VDC (100% full scale flow) setpoint
reference. Using the calibrator check the flow rate. If necessary, adjust R33 to
match the desired full scale flow rate. [In control mode, turning R33 clockwise will
decrease the flow. Conversely, turning R33 counterclockwise will increase the flow
through the GFC.]
7.3.10 25% Flow Adjustment
Change the setpoint to 1.25 VDC to control at 25% of full scale flow. Check the
flow rate indicated against the flow calibrator. If the flow rate is not within ±0.75%
of full scale, re-adjust the setting for potentiometer [R33], until the flow output is
correct.
7.3.11 50% Flow Adjustment
Change the setpoint to 2.50 VDC to control at 50% of full scale flow. Check the
flow rate indicated against the flow calibrator. If the flow rate is not within ±0.75%
of full scale, re-adjust the setting for potentiometer [R38], until the flow output is
correct.
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