Lincoln 85621, Service & Operating Manual, Page: 9 / 23

LINCOLN Model 85621 sm-rev0510 Form # 404160 Page 7
TROUBLESHOOTING
Possible Symptoms:
•
Pump will not cycle.
•
Pump cycles, but produces no flow.
•
Pump cycles, but flow rate is
unsatisfactory.
•
Pump cycle seems unbalanced.
•
Pump cycle seems to produce
excessive vibration.
what to Check: Excessive suction lift
in system.
Corrective Action: For lifts exceeding
20 feet (6 meters), filling the pumping
chambers with liquid will prime the
pump in most cases.
what to Check: Excessive flooded
suction in system.
Corrective Action: For flooded
conditions exceeding 10 feet (3 meters)
of liquid, install a back pressure device.
what to Check: System head exceeds
air supply pressure.
Corrective Action: Increase the
inlet air pressure to the pump. Most
diaphragm pumps are designed for 1:1
pressure ratio at zero flow.
what to Check: Air supply pressure or
volume exceeds system head.
Corrective Action: Decrease inlet
air pressure and volume to the pump
as calculated on the published
PERFORMANCE CURVE. Pump is
cavitating the fluid by fast cycling.
what to Check: Undersized suction
line.
Corrective Action: Meet or exceed
pump connection recommendations
shown on the DIMENSIONAL
DRAWING.
what to Check: Restricted or
undersized air line.
Corrective Action: Install a larger
air line and connection. Refer to air
inlet recommendations shown in your
pump’s SERVICE MANUAL.
what to Check: Check ESADS, the
Externally Serviceable Air Distribution
System of the pump.
Corrective Action: Disassemble and
inspect the main air distribution valve,
pilot valve and pilot valve actuators.
Refer to the parts drawing and air valve
section of the SERVICE MANUAL.
Check for clogged discharge or closed
valve before reassembly.
what to Check: Rigid pipe connections
to pump.
Corrective Action: Install flexible
connectors and a Surge Suppressor.
what to Check: Blocked air exhaust
muffler.
Corrective Action: Remove muffler
screen, clean or de-ice and reinstall.
Refer to the Air Exhaust section of your
pump SERVICE MANUAL.
what to Check: Pumped fluid in air
exhaust muffler.
Corrective Action: Disassemble pump
chambers. Inspect for diaphragm rupture
or loose diaphragm plate assembly. Refer
to the Diaphragm Replacement section
of your pump SERVICE MANUAL.
what to Check: Suction side air leakage
or air in product.
Corrective Action: Visually inspect
all suction side gaskets and pipe
connections.
what to Check: Obstructed check
valve.
Corrective Action: Disassemble the wet
end of the pump and manually dislodge
obstruction in the check valve pocket.
Refer to the Check Valve section of
the pump SERVICE MANUAL for
disassembly instructions.
what to Check: Worn or misaligned
check valve or check valve seat.
Corrective Action: Inspect check
valves and seats for wear and proper
seating. Replace if necessary. Refer
to Check Valve section of the pump
SERVICE MANUAL for disassembly
instructions.
what to Check: Blocked suction line.
Corrective Action: Remove or flush
obstruction. Check and clear all suction
screens and strainers.
what to Check: Blocked discharge
line.
Corrective Action: Check for
obstruction or closed discharge line
valves.
what to Check: Blocked pumping
chamber.
Corrective Action: Disassemble
and inspect the wetted chambers
of the pump. Remove or flush any
obstructions. Refer to the pump
SERVICE MANUAL for disassembly
instructions.
what to Check: Entrained air or vapor
lock in one or both pumping chambers.
Corrective Action: Purge chambers
through tapped chamber vent plugs.
PURGING THE CHAMBERS OF AIR
CAN BE DANGEROUS! Contact the
Customer Service Department before
performing this procedure. Any model
with top-ported discharge will reduce or
eliminate problems with entrained air.
If your pump continues to perform
below your expectations, contact your
local Distributor or Customer Service
Department for a service evaluation.
wARRANTY
This pump is warranted for a
period of five years for defective and
workmanship.