Chapter 4 Maintenance | Series 830/840/860 Instruction Manual |
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Valve Maintenance
Electromagnetic valves may require spring-tension adjustments for various reasons (See Valve Adjust Procedure). No maintenance is required under normal operating conditions other than an occa- sional cleaning. Use of certain corrosive gases may require fre- quent replacement of the valve plug and O-rings. This indicates a need for a different elastomer. Viton is standard, with Neoprene, Kal-Rez (or equivalent), and PFA Teflon offered as options.
Do not attempt any valve adjustments while the meter is “on-line” with any dangerous gas. All controllers should be thoroughly leak- tested following any valve adjustment.
For the Model 860 Auto-Trak, refer to “Piston Tube Calibration Procedure” for instructions on how to re-adjust the electromagnetic valve for proper operation.
Electromagnetic Valves - Low and Medium Flow Controllers
Caution! When using toxic or cor- rosive gases, purge the unit thoroughly with inert dry gas before discon- necting from the gas line.
Controllers with a low or medium flow body use the same valve; high flow models use a larger version. Cleaning can often be ac- complished by opening the valve, using the purge function and flushing in both directions. Alternatively, the valve may be manu- ally opened by loosening the 6-32 lock nut on top of the valve and turning the adjustment screw fully counterclockwise.
To disassemble the low and medium flow valve for inspection:
1.Remove the unit from the system.
2.Remove the two 4-40 Phillips head screws on top of the enclo- sure. Remove the enclosure by sliding it up and off. Remove the metal cap on top of the valve by inserting a flat tip screw- driver into the slots provided and prying upward.
3.Use a 5/8 inch nut driver to loosen and remove the 5/8 inch nut at the top of the valve. Remove the coil, coil enclosure and warp washer.
