March 2004
P h o n e : ( 5 8 5 ) 4 2 6 - 0 9 9 0
w w w . j e s c o a m e r i c a . c o m
F a x : ( 5 8 5 ) 4 2 6 - 4 0 2 5
PP 6.9
SD 6.9
Operation & MaintOperation & MaintOperation & MaintOperation & MaintOperation & Maint
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tructions tructions tructions tructions tructions
MA
GDOS DEDX
Problem
Possible Cause
Recommended Action
Pump fails to
inject chemical.
System shut off valves are closed
Open valves, prime pump.
Check valves are leaking.
Inspect connections. Clean valves and reinstall or
replace. (See Start Up, page 1.4.)
Suction filter, foot valve or suction line
is leaking or blocked.
Clean and seal suction line.
Check valves are incorrectly installed.
Reassemble check valves. Ensure that the balls for
the suction and discharge valves are correctly
positioned above the check valve seat (See
Maintenance Section, page 1.7).
Suction lift is too high.
Install pump at lower position or install a priming aid.
Viscosity is too high.
If viscosity reading is between 100 and 400 cps,
install spring-loaded valves. Enlarge suction line inner
diameter. Use special wetted head. (Consult factory)
Pump is not
stroking.
LEDs are off.
Check power supply line.
Pump is set to zero stroke.
Correctly adjust pump stroke length.
Low level jack is open.
Insert level probe plug or replace dummy plug.
Diaphragm return spring is broken.
Replace spring.
Solenoid is defective.
Check coil resistance and isolation, replace solenoid if
required.
Red low level
liquid indication
LED is blinking.
Supply tank level is low.
Refill supply tank.
Red low level
liquid indication
LED is on.
Supply tank empty; level control or
dummy plug incorrectly inserted.
Fill supply tank or check suction line float. Check
dummy plug or cable connection.
Pump is
experiencing
frequent
diaphragm
failures.
Back pressure at discharge connection
is too high.
Check system pressure. Possible blocked injection
nozzle. Install pulsation dampener to even out flow.
There is sediment in metering head.
Flush metering head. Install screen on foot valve.
Diaphragm was not properly tightened
into diaphragm rod.
Tighten diaphragm. Support plate must then be
positioned between diaphragm and diaphragm rod.
No diaphragm support plate.
Replace diaphragm with support plate.When
replacing diaphragm, check if deflector plate or
diaphragm rod have been corroded by process fluid.
Pump is
delivering too
much chemical.
Stroke knob shifted.
Recalibrate knob (See Maintenance Section, page
1.7).
Stroke frequency is too high.
Reduce frequency.
Suction pressure too high (pump
siphoning).
Install back pressure valve in discharge line.
7. Troubleshooting
