Troubleshooting, Pressure test, Diaphragm test – I.C.T.C. Holdings Corporation 300S Legend User Manual

Page 17

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300S / 300SL LEGEND Owner’s Manual




To verify the performance of an airless sprayer, use of pressure gauge is required. A pressure gauge (min.
3000 psi) installed at the gun, using a new .021 tip, and not less than 50 feet of H.E.R.O. airless spray hose is
needed. If you do not have access to these items, your local H.E.R.O. authorized service center will be able
to perform this test. Your model 300S/SL is manufactured to perform at;

2650 psi -- Static pressure, with lock ring (ref# 76) on pressure control va lve (ref# 73).
1950 psi -- Pressure drop, when gun trigger is squeezed.
2250 psi -- Spraying pressure, after recovery time.

If your unit is unable to perform to the above pressure levels consult the troubleshooting guide for the
required repair procedure.


If your unit is disabled and you are unable to perform a pressure test, use the following procedures for
determining the area to repair. This test will divide the two halves of the equipment (hydraulic from paint)
and make identification of your solution easier to obtain. This test is commonly referred to as the
"Diaphragm Test"

The solution to almost all problems can be found in the paint side valves, due to the increased wear from
contact with the abrasive paint/spray materials. Intake valve assembly (ref# 11-15), Outgo valve (ref# 22),
and Prime valve (ref# 34) make up the three paint valves. Refer to pages where exploded views of these
valves are shown. To eliminate the hydraulic side of the pump
(piston side of diaphragm) as a source of problems;


Remove the intake valve end cap (ref# 11) by removing the
four cap screws (ref# 9 ).


Remove large spring (ref# 15).


Start unit.


Increase the pressure by turning the pressure control knob
(ref# 74) clockwise to full pressure.


Put pressure on the center of the exposed diaphragm with the
handle of a screwdriver or other blunt object. NOTE: The
diaphragm is located between the paint head (ref# 18) and
the hydraulic head (ref# 53


If you are UNABLE to stop or alter the hydrapulse
membrane's movement, then the hydraulic side is operating
properly. The problem is located in the “Paint” pump. See
troubleshooting guide for additional information.