SELWOOD SELTORQUE S150, Manual

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Selwood Seltorque S150 Manual
22
7 FAULT FINDING GUIDE
This table gives the most common symptoms arising in connection with water handling duties. Please consult
Selwood Pumps for further advice if the service fault is not described, and particularly if the duty has uncommon
characteristics.
At no time should the pump be run if its bearing housing or flushing chamber contains contaminated oil. Very small
volumes of oil may be lost from these chambers during a day's normal running, but remedial action should
immediately be taken if the loss becomes excessive. The most likely causes of failure are given in the sequence in
which they should be investigated. For example, if the pump will not prime, carry out the first service instruction that
is listed and proceed to the second only if the first proves to be inappropriate.
PUMP WILL NOT PRIME, OR LOSES PRIME HAVING PUMPED PRODUCT FOR A BRIEF PERIOD OF TIME
ACTION COMMENT
1 Check that drain taps fitted to volute and air
pumps are closed. Drain taps are sometimes left open overnight. If okay,
try Action 2.
2 Remove inspection cover and check that
delivery valve is seating efficiently. The delivery line MUST BE DRAINED before the cover
is removed. If okay, try Action 3.
3 Disconnect hose from air pump spigot and
attach vacuum gauge to pump - should read
29' H20 (25.6" Hg) or more, after the pump is
stopped. If vacuum is okay, check Action 4.
If vacuum is low or fails quickly, check Action 8.
4 Reconnect air pump hose, and check vacuum
at suction spigot of main pump. Correct
reading is given above. If vacuum is okay, check Actions 5(a) and (b).
If vacuum is slow to rise or low at terminal condition,
check Actions 6 and 7.
(a) Check all suction side hoses, fittings
and joints for air leaks.
Priming problems are VERY often caused by faults in
supply pipework. Air must not be allowed to pass into
the system across couplings, etc. 5
(b) Check strainer and suction hose for
blockages.
Do not use non-reinforced hose. Always fit a strainer of
correct size and type.
6
Examine separator assembly for air leaks or
trapped solids. Check peel valve seat for ice
in cold conditions. Refer to Section 5.2 Separator Maintenance for
instructions. The float must be able to rise and fall
freely. The peel valve must completely shut off the air
pump when the float rises to its maximum position.
7 Check level of oil in flushing chamber. If level is very low, mechanical seal may be admitting
air. Top up, and re-check vacuum. Substantial oil loss
indicates seal failure - refer to Section 5.3.2 Mechanical
Seal (C08) for instructions.
8 Examine valves and flexing seals in air pump
assembly and check that castings are not
cracked. Refer to Section 5.1 Air Pump Maintenance for
instructions.
OUTPUT AND HEAD ARE LESS THAN PUBLISHED FIGURES
ACTION COMMENT
1 Check strainer and suction pipework for
blockages. Also check that air is not being
pulled through a vortex created in the supply
reservoir. Choking of the supply system by solids will increase the
flow resistance, thus increasing the head against which
the pump has to operate, and so reducing output. The
entry of air through faulty pipe joints will have a similar
effect. Reduction also occurs if air is entrained through
a vortex - to eliminate, increase strainer's submergence.
2 Check pump speed with tachometer. Speed, off load must not exceed 1600rev/min.
3 Check that delivery valve, discharge branch of
casing, and pipework are free from blockages. Obstructions downstream of the pump will increase the
flow resistance and thus reduce output.
4 Check condition of impeller. Excessively worn vanes will reduce output. Also check
outside diameter of vanes:
Standard Seltorque S150
Standard Dia.
235mm
Smallest Dia. 219mm
Contact Selwood with pump number to confirm correct
impeller variant fitted.