Troubleshooting
18
313937A
Troubleshooting
Problem
Cause
Solution
Pumping (after satisfactory startup)
Pump stalling and no material being
pumped despite adequate input
pressure
Blocked mixer.
Turn oil-air supply and remove hoses
from mixer. Check hoses for flow.
Closed outlet ball valves.
Open ball valves.
Blocked check valve.
Unlikely to be fully restricted, but
possible. Dismantle, clean, and rein-
stall.
Pumps cycling satisfactorily but total
material output dropped off, or one
pump output legs behind the other.
One pump metering incorrectly.
Check both outputs from the hoses.
If pumps are out of phase or if one
pump is not discharging a full shot of
material, see next solution.
Pumps not discharging normal or full
volume
Low material level in reservoirs.
Refill reservoirs. Prime pump and
hoses.
Air in material (normally only high
viscosity material)
Reload reservoir with minimum air
entrapment. See “air in hose” solu-
tion.
Piston worn or broken.
Remove and inspect suspected pis-
ton. Replace if worn or damaged.
Check valve malfunction.
Remove, clean, and reinstall the
check valve.
Pumps not cycling at all or pumps
not completely cycling.
Air circuit failure.
See Logic Circuit troubleshooting.
Pumps drawing material back down
from hose.
Check valve stuck open.
Remove check valve and clean or
replace.
Material continues to flow stop dis-
pense stroke, or air bubble apparent
at some part of the dispense stroke
each time
Air in hose. Hose not primed cor-
rectly.
Incline hose from check valve to out-
let of the hose. Avoid sags in hose.
Cycle machine until all trapped air is
discharged.
Snuff-back not adjusted properly.
Increase or decrease the amount of
snuff-back, as needed.
Air in material entrapped during res-
ervoir refill.
Reload reservoir with minimum air
entrapment. (Ask for technical ser-
vice).
Air in material -- being drawn into
pump from behind check valve.
Remove check valve and fitting in
front of pump. Reinstall with PTFE
tape.
Air in material -- being drawn into
pump through shaft seal area, pump
tube, or shaft seal block o-ring joints.
Tighten shaft seal and if badly worn,
replace. Replace and reinstall
o-rings.
Air in material -- being drawn into
pump through inlet hoses or coupler.
Tighten or seal as necessary.
Severe leaks at pump shaft.
Pump shaft seals worn.
Remove pump packing assembly
and replace shaft seal set.
Summary of Contents for Pneumatic PR70
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