11
The pump
runs but
gives no
water
The non-return valve is stuck
in its shut position
The discharge valve is
closed
No water or very low level in
borehole
The inlet strainer is choked up
The pump unit is defective
The pump
runs at
reduced
capacity
Leakage in the pipework
Pipes are leaking
Pull out the pump and clean
or replace the valve
Open the valve
Increase the installation
depth of the pump, throttle
the pump or replace it with
a smaller model to obtain
reduced capacity
Pull out the pump and clean
the strainer
Replace or repair the pump
The valves in the discharge
pipes are partly closed or
blocked
Check and clean or replace
the valves and discharge
pipe
The pump is defective
Repair or replace the pump
Check and repair the pipe
work
The non-return valve of the
pump is partly blocked
Pull out the pump and check
or replace the valve
The pump and the riser
pipe are partly choked by
impurities
Pull out the pump. Check
and clean or replace the
pump if necessary
The draw down is larger than
anticipated
Increase the installation
depth of the pump, throttle
the pump or replace it with
a smaller model to obtain a
smaller capacity
Replace pipes
