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8. Failures and Remedies
If you have trouble with your pump, you may be able to help yourself by reading the tips we give you below. If you cannot
find the reason for the trouble, call a plumber or write to us, not forgetting to mention the pump model and its serial
number.
Prior to doing any work on the pump, switch off the electricity and make sure that the pump is idle
and the pressure at zero.
8.1 Little or no water at all is being pumped
Possible Reason Remedy
a) Pump is running but delivers no water even though
it is filled properly.
Remove air chamber (5) and loosen rubber valve discs (113/123) which have probably
got stuck if the pump has been stored for a long time.
b) Not sufficient water in the pump. Refill pump as explained in 6.2 and at the same time turn the pump several times pouring
in water little by little till there are 2-4 litres in the pump. Screw on filler plug (33) again and
seal carefully. More water may be necessary if the suction line is very long or the suction
head very high.
c) Suction head too high / suction line too long. Measure difference between water level and pump flange connection (fig. 111/I).
Compare loss of friction in long pipes with table (available upon request) and add the
difference in height.
d) Suction line is not seal-proof. After the pump has been running for a while, check whether air bubbles can be seen
through transparent hose (Fig. 111/II) above elbow on tank. If so, press out air, find leak
and make it seal-proof.
e) Soiled or worn-out valves Pebbles, hemp, shavings etc. coming from new wells often get absorbed into the pump so
the air chamber (5) has to be removed and the valves checked. Loosen nuts above valve
bridge. Remove valve bridge and any crust which may be on it. Valves are not screwed in.
If they are stuck, press them loose with the handle of a hammer. The valve seat seal is
under the valve - make sure that the seat is clean. Rubber valve discs (113/123) may
have to be replaced if the pump is old.
f) Stuffing box is not seal-proof. Tighten up nut (6a) a little. If this does not help, replace packing rings (6d) and possibly
seal rings (6b) as well. Do not use hemp, we use Teflon-impregnated packing rings.
8.2 Pump Knocks
Possible Reason Remedy
a) There is no air cushion in the air chamber Make sure that the air volume control (Fig.111/III) is working properly. The snifting valve
should hiss when the pump is running. Check whether rubber lip (29a) is dirty or clogged.
Air could be escaping through screw on filler plug, therefore check by covering sealing
surfaces of air chamber and filler plug with a soap solution.
b) Pre-pressure in pump Water level in pump/air chamber is too high because snifting valve has not absorbed enough
air. Install regulator in suction line (s.5.5/5.6). Pump should run with about 5 metre vacuum
ensuring that sufficient air is pumped.
c) Pump suction head is very low Same applies here as explained under b). A vacuum must be provided by means of a
regulator so that sufficient air will be pumped.
d) High suction head - long suction line Install a suction air chamber as per 5.4 and ensure sufficient ventilation. Make sure there
is enough water in the well, e.g. after a dry season.
e) Conrod bearings in pump deflect You can not always determine the reason for knocking by ear, so you have to turn the V-
belt pulley (18) backwards and forwards to determine any clearance between bearing and
conrod. Repairs to the gear are best done by a skilled tradesman.
f) The pump V-belt pulley deflects and does not sit
properly on the crankshaft
As described under e).
g) One of the ball bearings is defective As described under e).
8.3 Pump switches on when very little water is discharged and switches off immediately the tap is turned off
Possible Reason Remedy
The air cushion is not filled up sufficiently. During
initial operation, there may not have been enough air
pumped into the tank or the air the pump has pumped
into the tank is escaping somewhere (pressure
switch, pressure gauge, air volume control, pump
connections, transport damage).
If snifting valve and air volume control are working properly (111/III) and there still is not
enough air in the tank, coat all threaded connections on tank with a soap solution to
determine where it is leaking. It could also be that the pressure switch (111/IV) is not air-
tight.
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