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SERVICE NOTES / FAULT DIAGNOSIS
GENERAL
For current
owners, the most likely wear parts of the hydrostatic test unit are
the pump hydraulic seals and the hydrostatic return valve,
panel valve number 6 on the units. Service kits are
available for the panel valves (part number 20157099k) as well as
the Haskel® MS series pumps. Airdive strongly recommends that
customers only use genuine Haskel® parts in pump repairs as
non-genuine parts generally fail within weeks. Airdive can
service the MS series range of pumps if required. The same
applies for Kempe Fluid Air pumps. Genuine Fluid Hydraulics
parts should be used if a Fluid Hydraulics (Kempe) has been fitted
to the test unit.
IMPORTANT -If
working on piping or valves of unit make sure all pressure is
relieved from unit, both hydrostatic and air pressure or injury
could result. Check the gauge pressure of all gauges which
should be reading zero pressure and open all high pressure section
gauges. Open pump drive vent valve to vent residual air in
hydrostatic pump. Remember SAFETY FIRST!
ALWAYS WEAR EYE
PROTECTION WHEN OPERATING UNIT IN CASE OF AIR OR HYDRAULIC PIPE OR
FLEXIBLE LINE FAILURE DURING OPERATION
Airdive strongly
suggests the unit be mounted in such a way that the back of the
unit is easily accessible for service and inspection such as on a
solid frame.
If working on piping, always use two spanners so
that fittings are not damaged. Do not over-tighten olive
fittings or they will need to be replaced including the pipe
section if damaged. All piping used in test units is
1/4" (6.35) diameter of 3/8" diameter. Do not mix
metric piping and imperial ferrule sets.
All units a
checked in factory before shipment. If alteration to the
drain pipe (pipes) from sight glass tube(s) supplied with the unit
is required, contact Airdive for details first as incorrect drain
pipe alteration will cause incorrect readings to result. All
drain pipes must be free flowing and open into larger bores or
airlocks will result.
PANEL VALVES
If fitting a replacement panel valve take note of
the inlet / outlet ports before disassembly so that valves are
placed in the correct orientation (direction). On valve 6 of
the unit, the inlet side must be toward the high pressure section
of the test unit (inlet port faces towards centre of unit)
with cross
pipe assembly up to gauges) and the
outlet port faces towards outside of case with return pipe to
bottom of pump inlet. If this is not done then difficult
operation of the valve will occur and possible gauge damage through
rapid depressurisation could result.
Panel valve 6 will wear out over time. Seat pitting
through fine particles of rust from cylinders or from the water
supply itself do find their way into the water. Water filters prior
to the inlet to the unit can prolong seat and pump seal life in
areas with high mineral content water supplies such as Western
Australia. Check seat condition before installing a new
service kit. A torch will assist this inspection greatly.
NOTE! If the hydrostatic return valve (number 6)
leaks, the test unit will not hold pressure as water will leak back
to the low pressure
side.and back into the reservoir tank.
If the test unit will not hold pressure but shows no water
loss, then a leaking hydrostatic return valve is the most likely
problem. Alternatively there could be a dual inlet/outlet
check valve failure in the hydrostatic pump but this would be very
unusual.
If there is water loss from the system
then there is a system pipe leak or a faulty hydraulic seal in the
hydrostatic pump.
HYDROSTATIC
PUMPS
If the exhaust section (muffler) shows misting of
water during operation and there is difficulty in maintaining
pressure or the unit seems to be loosing water then the likely
explanation is worn hydraulic seal in the hydraulic seal section of
the pump. The pump must be removed and the hydraulic seals
replaced. If it is suspected that there is a hydraulic lead
fix the pump as soon as possible as this will prevent corrosion of
the internal return spring and damage to the air drive barrel
through corrosion. Further, if the pump is leaking then the
unit cannot comply with the relevant testing standards until the
unit is repaired as inaccurate test results will occur. Note!
wetness on the muffler is normal in clod weather as the cold air
being exhausted from the pump condensed moisture in the air on cold
days. If in doubt put the blank plug in the test hose and
pressurise the unit to 40 MPA up to 10 times. Don't add
water. The water level should be a the same level set at the
beginning of the process. If there is progressive water loss
each pressurisation, there is a water leak.
AIR REMOVAL FROM SYSTEM -GENERAL
GUIDELINES
For proper operation all air must be removed from
the system. This is most successfully carried out using the
blanking plug fitted to the outlet hose assembly. Air should
be forced to the top or the unit using the water supply. Keep valve
2 closed during this operation so that water does not
preferentially fill the reservoir tank at the side of the unit.
Open valve 8 at the top of the test unit and allow the water
to drain from the top of the unit outlet by opening the water fill
valve (valve number 1). When no more air can bee seen in the
outlet water the valve is closed off and the reservoir tank is then
filled as per tank top up. Valve 6 should be alternatively opened
and closed during this operation. The air drive valve (number
3) can be opened to run the pump to force water and trapped air
from the top of the unit as well, but valve 6 must be open or
pressure will build up in the high pressure side of the unit when
you do this. When complete return all valve settings to
normal operating settings and remove the blank plug. The unit
is now ready to continue hydrostatic testing.
SYSTEM DOES NOT HOLD PRESSURE (PANIC STATIONS!)
If the system will not hold pressure or get to a
specified pressure, firstly check for water leaks from fittings and
attachments on the high pressure water side of the apparatus.
Repair / tighten as required.
If test pressure cannot be achieved, check the
water level in the sight tube above the reservoir. If water
is returning to the sight tube then the likely problem is a leaking
hydro return valve (number 6). Replace the valve seals and
seat with service kit 20157099K. Inspect the metal valve seat
of the valve body for damage, pitting, cracking or wear before
installing the kit. If the metal valve seat is damaged then a
new seal kit will either leak immediately or leak water back
to the reservoir in time. If the valve body is damaged then
replace the panel valve (part number 201570H).
If water is being lost from the system as evidenced
by a water level drop in the sight tube when pressure is returned
to zero pressure, then it is probable that the pump hydraulic cup
seal is faulty and will need replacement. If the seal is
faulty it leaks water into the air drive side of the Haskel® pump
which is subsequently blown out through the exhaust muffler during
pump operation. Look for moisture at the muffler or a water
spray pattern in the rear of the unit. Don't get confused
with normal condensation which settles on the exhaust during cool
weather. If a pump seal leak is suspected then pump
must be removed by releasing all air and water pressure from the
unit, and dismantling the low pressure and high pressure piping
attached to the pump. Once this is achieved, the two pump
mount retaining bolts can be removed which holds the pump support
to the tester case. Always use two correctly fitting spanners on
all fittings and don't force pipe fittings or twist piping or gauge
damage can occur. If a pump leak is suspected fix it promptly
even if the pump will get to pressure. Water loss will give
incorrect test readings which could lead to incorrect cylinder
failure and also cause more costly pump repairs as the internal
return spring will rust which in turn can cause damage to other
components. If in doubt, get it fixed.
All test units are supplied with a blanking plug
(2940TP15B) which can be fitted to the end of the test hose.
Use this to speed up diagnosis of faults as you will not have
to pressurise a cylinder. Using the plug will mean that a
system pressure of 40 MPa can be achieved while still having water
visible in the sight tube enabeling visual inspection of water
leaking back to the reservoir (in the case of valve 6 leakage).
Cycling the unit up to 40 MPa and back to zero pressure 5-6
times with the blank plug installed with no addition of water
between cycles will confirm a pump/system leak if the water level
in the tube drops each cycle.
Very occasionally the top panel vale which is
utilised when attacking the Master test gauge can wear and leak
which will also cause water loss from the system (if no gauge is
attached to the outlet - top right hand side). This could be
confused with a pump leak so check for leakage at this point as
well. Generally a panel valve kit (20157099K) will solve the
problem as this valve is subjected to less use and metal valve seat
wear is less likely to occur - check the metal seat though just to
be sure.
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