MDE-4334C Atlas Start-up and Service Manual · April 2008
Page 7-71
Valves
Hydraulic/Mechanical Components
3
Replace valves and/or coils if readings are out of tolerance.
4
Use UL-approved sealant (as required) while replacing valves. Do not use Teflon tape.
5
Clean the valve area. Do not introduce contamination.
6
Install valves with the flow arrow in the proper direction.
Note: Two-stage valve torque specifications on hex hd. bolts is 130+/- 10 inch. lbs.
Meter Check Valve
Figure 7-34: Check to Meter Orientation
O-Ring
Solenoid Valve and
Filter Manifold
Check Valve
O-Ring
Meter
Potential Problems
• Damage to hydraulic parts can occur from thermal expansion or driving over a hose, if the
valve is inoperative.
• If a valve sticks open, a sale may register when you first turn the nozzle hook On with the
nozzle closed. Check STP check valves for problems.
• Blend error codes indicating product contamination
• Stuck valve can cause reduced flow rates
• Leaks
• Calibration problems
Service Steps
• Check valves are not rebuildable. Replace any defective check valves.
• Wear eye protection while replacing any check valve.
To service valves, proceed as follows:
1
Close and test shear valves for dispensers.
2
Shut off power to the unit and any involved STPs. Use OSHA Lock-out/Tag-out procedures.
