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Checking the valve
•Remove the position indicator from valve cover.
•Check that the valve spindle moves easily by raising and lowering it with the threaded rod.
•Install the optical position indicator.
Putting the valve back into service
•see chapter Commissioning
Checking the operation of the valve
The pressure-sustaining valve has to be set eventually in such a way for the check that the inlet pressure
permits the opening of the valve (see also the Chapter: Commissioning).
•Close the ball valve (2C) slowly; Valve must close.
•Open the ball valve (2C) slowly; Valve must open.
2.3 Four or five annual maintenance
Cleaning the strainer in the main supply
•Unscrew the lid
•Clean the filter with a brush or cloth, or replace it
•Refit the filter and screw the lid back on
Cleaning the filter in the control line
•Unscrew the lid of the filter
•Clean the filter with a brush or cloth, or replace it
•Refit the filter mesh and screw the filter lid back on
Main valve (see chapter: Repair kits and spare parts)
•Undo the fittings of the control line and lay the complete control line aside.
•Disassemble the Optical Position Indicator and replace the gaskets
•Undo the screws of the valve cover and remove this valve cover.
•Visually inspect all inner components for wear, dirt and scaling
•Clean inner components, seat and inner surfaces including the valve cover
•Disassembly the spindle guide at the housing, rinse the housing interior.
For valves from DN 40 to DN 100 built in 2012 and DN 125 to DN 200 built in 2014, the spindle
guide has to be removed from inside of the housing. The guiding thread of the spindle and the base
valve must be extremely clean. Grease the thread well (eg Food Grease Aqua, Item No. 5292, see
chapter control line parts and accessories).
•Replace the diaphragm, the O-ring and if necessary also the seat seal
•Thinly grease the area around the spindle guide with an agent, which is suitable for contact with
foodstuffs. Check for easy movement of the spindle in the housing guide and in the cover guide.
•Assemble the main valve (See torque table in Annex). During assembly the easy movement of the
spindle must be checked several times by actuating the threaded rod.
Disassembling the control valve (see chapter: Repair kits a spare parts)
•Undo the screw on the hand wheel
•Turn the hand wheel counter-clockwise until no resistance can be felt from the spring
•Undo the housing screws.
•Replace the diaphragm, the O-ring and, if necessary, also the seat support
•Visually inspect the inner surfaces of the housing and clean if necessary, including the cover, item 2
•Re-assemble the control valve (See torque table in Annex).
•Refit the fittings of the control line that had been put aside.