Call or Visit @ 248-624-7710 / www.dedoes.com
Manual Propor�oning Unit
Dedoes P# MPU02
P# SA0255 & SA0256 Check Valve Cleaning Instruc�ons
About one inch
• Pour about one inch of Reducer in two chemically resistant containers.
• To prevent cross contamina�on, use separate containers for the Front
and Rear pump check valves. Place the check valves in the fluid for about
twelve hours. Then, while wearing gloves, use a small brush to lightly scrub
the outside and inside of each check valve while the valves are s�ll in the
fluid.
• Stand the check valves up in the fluid with the arrow pointed downward.
Insert a small Allen wrench into the inside of each check valve and push
downward on the piston between the ends of the snap ring. Con�nue to
move the piston with the Allen wrench un�l it moves up and down and
returns to the snap ring freely. If the piston will s�ll not move, use a
hammer to gently tap on the top of the Allen wrench while it is in contact
with the top of the piston between the snap ring. If this does not free the
piston to move freely and return to the snap ring, you will need to order a
new check valve. P# SA0255 Discharge Check Valve or SA0256 Suc�on
Check Valve.
• Blow the check valves off using low pressure compressed air. Then with
the Allen wrench, check that the pistons are s�ll moving freely and
returning to the snap ring.
• Correctly reassemble the MPU Pump Assemblies and check valves.
- The SA0255 DISCHARGE Check Valve has a five pound crack pressure.
Replacement Discharge Check Valves will be marked with a D on them.
- The SA0256 SUCTION Check Valve has a one third pound crack pressure.
Replacement Suc�on Check Valves will be marked with a S on them.
• Pushing on the piston with an Allen wrench can easily iden�fy each
valve. The Suc�on Check Valve with it’s one third pound crack pressure will
be much easier to push open than the Discharge Check Valve with it’s five
pound crack pressure. Once you have iden�fied each valve, assemble the
check valves to the pumps using thread sealant. Be sure that the arrows on
the check valves point in the direc�on of the fluid flow.
• Use separate containers for the front and the rear pumps to prevent
cross contamina�on. Test the assembled MPU unit using Reducer or
Acetone. Pump all the fluid from the unit a�er tes�ng, and dry all fluids
from the suc�on tubes and discharge hoses using paper towel.
• Perform a pressure test to check for leaks prior to use. See page 1 for
Pressure test steps.
Front Valves
Rear Valves
Push down
here.
Snap Ring
SA0255
Discharge Check Valve:
Replacements are
marked with a “D”
These have a 5 Lb crack
pressure.
SA0256
Suc�on Check Valve:
Replacements are
marked with a “S”
These have a 1/3 Lb
crack pressure.
12 Hours