9
Fair Wear / Tear?
Check – Replace HP Jet
Check Recent
Activity/Usage
Suction/Delivery HP Outlet Valves
Worn
Check – Replace
Therefore Check suction
Filters
Unloader Valve Worn
Replace as required
Piston Seals Worn
Replace as required
Check Big Ends for Piston
Slap
Piston Cracked
Replace as required
Check Big Ends for Piston
Slap
”O” Rings Failed/Leaking
Replace as required
”Big End” Worn
Replace as required
PSI LOW AFTER
PERIOD OF USE
Drive Belts Loose (if belt driven)
Check / Tighten
Air in Suction / Pump Cavitating
Identify Air Ingress/Seal
Problem with pump-motor
connection
Check gearbox or coupling
Broken or Weak Suction Valve
Spring
Check – Replace – As Set
Valves Clogged/Sticking
Check – Replace – As Set
Worn Main Crankshaft Bearings
Probably Uneconomical to
Repair
PUMP VERY
“NOISY”
Inlet Water Temp over 75 deg
Celsius
Reduce inlet Water Temp
Left in By-Pass for
excessively long periods?
Piston to Crankcase Oil Seals Worn
Check and Replace
Look for Oil under Pump –
Low Pump Oil
Condensation from High Ambient
Humidity
Replace oil more frequently
Piston Seals Worn/Cracked Piston
Check – Replace
OIL IN PUMP
EMULSIFIED/
CONTAMINATED
BY WATER
(water in the
oil)
Water Blasted into Pump via
Breather Cap during Cleaning
Exercise Care
H.P. Piston Seals Worn or
Check and Replace Seal Pack
Worn Plunger
Replace Plunger
Worn Plunger Stop Seal
Replace Seal
WATER
DRIPPING FROM
UNDER PUMP
(Between
crankcase and
manifold
housing)
“O” Rings in Plunger Retaining Bolt
Worn
Check and Replace
OIL DRIPPING
FROM UNDER
PUMP
(Between
crankcase and
manifold
housing)
Piston to Crankcase (Plunger Shaft)
Oil Seals Worn
Check and Replace
Check Pump for Low Oil
therefore “Big End”
Damage
Accumulator Failed
Check – Replace
Worn Seals (Wet end seals)
Replace if worn
Worn Plunger Seals
Replace if worn
In/Out Pump Valves Worn
Check – Replace
Valves full of scale/dirt
Clean or replace
Pistons Cracked
Check – Replace
Low Water Supply
Increase supply
EXCESSIVE
VIBRATION/
PULSATIONS IN
HP DELIVERY
LINE
Gudgeon Pin in Conrod Stretched
Check – Replace
WATER FILTER
MESH IS
CRUSHED WHEN
REPLACED
Incorrect replacement procedure
on Grey NY126 Water Filters with
Blue or Red mesh tube
First insert mesh tube tightly into
the fixed black head of filter
assembly and then screw on grey
cover /cup tightly.
For small black filters, first
insert mesh tube into cover
/cup and then screw onto
fixed part.
