Electronics FC-24 - Manual (Page 7)

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E. SYMPTOM: High flow alarm or flow continues when set point is reduced or Enable is
turned off.
The MagnaValve is leaking shot. This is usually caused by a pressure difference above
and below the valve. Direct pressure air blast systems: The boost air pressure must be
equal to the pressure vessel pressure. Gravity fed (suction) air blast systems: The suction
induced by some venturi nozzles is quite large. Be sure there is a large (1/2") aspiration
air inlet near the bottom of the MagnaValve. The shot needs air to convey it to the nozzle.
Older practice was to "choke" the shot like a carburetor to get richer flow rate. Since the
MagnaValve acts more like a fuel injector, this choking is not required.
F. SYMPTOM: Shot flow rate is unstable.
1. New installations - refer to servo adjustments.
2. Old installations - machine worked fine until recently.
3. Check shot for cleanliness.
4. Check shot for cleanliness.
5. Check shot for cleanliness.
6. Do not make any servo adjustments.
7. Call the factory for advice.
8. NOTE: This category is the most challenging to troubleshoot. Shot cleanliness and for-
eign objects are usually the problem. Items such as: wire, welding rod, nuts and bolts
from the machine or screen separators, masking tape, razor blades, milk cartons, ciga-
rette butts, etc., seem to find their way to the valve. Remove the MagnaValve and in-
spect it for contamination. Be sure the shot hopper does not have contamination.