Maintenance - Edson 120E Installation And Operation Manual

Pump Speed: The proper speed depends on the application, what type of liquid is being pumped and the
head conditions. The following guidelines apply for this pump.
Maximum Cycle Rate is 60 RPM on the output shaft of the gear reducer.
The higher the viscosity the slower the pump. Viscous liquids need time to respond to
pumping pressures.
1 1/2" ID plumbing requires pump speeds under 45 RPM.
Small suction lines under 1 1/2" ID require speeds under 20 RPM.
The higher the back pressure the slower the pump RPM.

Maintenance

Diaphragm: Edson 120 Pumps use Elastomer Diaphragm and Flapper Valves. Over time these parts
wear and need to be replacement. The ability to easily and quickly replace these inexpensive
parts is one of the major advantages of an Edson diaphragm pumps. Edson has packaged these
parts as Spares Kits. See the parts list for the order #s.
Change the diaphragm as required. See Fig. 22
Inspection and testing on a regular basis is recommended. For continuous duty application,
inspect the pump daily until a life pattern is established.
Look for leaks, cracks or splits on the surface of the diaphragm.
Life expectancy is directly related to head conditions, run time and diaphragm material. The
higher the suction and discharge pressures the shorter the life.
Step 1. Unbolt Pump Base from
Pump Frame with 7/16" wrench.
Valve Assemblies & The Valve Seats: The sealing of the flapper valves are what makes the diaphragm
pump work. If the valves are not sealing properly, the pump will not be performing to full potential
or may not be pumping at all. The valves tend to last longer than the diaphragm. When you
change the diaphragm inspect the valves for cracks and delamination and the valve seats for
pitting and any build up that will prevent the valve rubber from sealing effectively. Testing the
pump is the best way to evaluate performance.
Change the valve assemblies as required. See Fig. 23
Inspection and testing on a regular bases is recommended. For continuous duty application,
inspect the pump daily until a life pattern is established.
See Pump Performance Tests (Page 8).
Step 1. Unbolt the Inlet and the
Discharge Chamber.
Step 2. Inspect Valve Seats.
Surfaces should be smooth,
flat and free of foreign matter.
Fig.23
146 DUCHAINE BLVD., NEW BEDFORD, MA. 02745-1292
Lock Out Electrical Service or Unplug the Pump Electrical Line
Before Performing Any Service.
Failure to Do So Will Result In Bodily Injury
Step 2. Unbolt the Diaphragm
from the Eccentric Housing and
Lower Standard (
) with 9/16" socket.
BACKING PLATE
Fig.22
Valve
Weight
Valve
Screws
Assembl y
Discharge Valve
Seat
TEL. 508- 995-9711
Page 7 Maintenance
Warning
Step 3. Reverse steps 1 & 2
to reassemble pump with new
diaphragm and the 2 sealing
STAINLESS STEEL
washers on the 3/8" bolts.
Important:
Eccentric stays connected to the reducer.
Lower Standard must be installed with it's sharp
edge away from the bottom of the diaphragm
Tools Required:
9/16" Socket Wrench with a 6" Extension
(2) 7/16" Box Wrench
Step 3. Resurface, if neces-
Valve
Inlet
Assembl y sary. Use a flat belt sander or
medium grade emery cloth
wrapped on a flat piece of
wood. It is important that the
Valve valve seat area remains flat.
Seat
Step 4. Install New Valves.
Insure Valve Weight Screws
are Tight and Valves are
Oriented Properly.
FAX 508-995- 5021 E-MAIL pumps@edsonintl.com
P-98-120E pg. 7