Series 830/840/860 Instruction Manual | Chapter 4 Maintenance |
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the no-leak condition). Now, adjust this screw clockwise one quar- ter turn past this point, tighten the locknut and replace the cap. Apply power and test the controller for proper operation.
(Quick fix for oscillation). If your unit is experiencing oscillations at lower flows, apply power, apply the desired setpoint, and adjust the valve spring adjustment screw ¼ turn at a time clockwise (in- creasing the spring tension – see procedure above) during flow un- til the symptoms disappear. Adjust ¼ turn further and tighten the locknut.
If your unit is experiencing other symptoms listed above, you may require this more involved adjustment method. Obtain a voltmeter and prepare to monitor the voltage found on pins 4 to 6 on a D-connector, or D to F on a card-edge connector. Or, if these pins are inaccessible, turn off the power and remove the cable.
1.Remove the screws and/or nuts on the top of the controller electronics cover. Cut the yellow calibration sticker. Remove the silver zero and/or span plugs on the right side of the enclo- sure or turn the plastic access-hole doors to the vertical posi- tion. Pull the cover up and off. Re-connect the cable, apply gas pressure, and apply power to the controller. Connect a voltmeter to the two wires on the back PCA that are routed to the solenoid and set the scale for 30 volts or higher.
2.Determine if this controller has a 15-volt control circuit or a
30-volt control circuit. (Don’t confuse this with the setpoint or output signals – this is an internal voltage that energizes the valve coil to raise the valve seat and open the internal orifice). M and H instruments are ALWAYS 30-volt circuits, while L instruments can be either one, based mainly on their flow-rates. Units scaled for below 10 slpm are typically set up for 15 volts while those 10 slpm or over are set up for 30 vdc. (Note: this voltage is typically listed on the calibration certificate in the “Comment” section). If there is any question, contact the fac- tory for clarification.
3.Apply a 100% set point and monitor this valve voltage, allow- ing at least three minutes for stabilization. The voltage “win- dow” for a 100% setpoint is 13-18 volts for the 30-volt circuit and 9-11 volts for the 15-volt circuit. If the voltage is out of this specification, loosen the lock nut, and adjust the center ad- justment screw. Clockwise (downward) will increase the valve voltage, while counterclockwise will decrease it. Adjust
