Grundfos SCALA2 Instructions Manual page 23

Fault
System overpres-
sure.
You can reset the
pump, but it runs
only for a few sec-
onds.
You can reset the
pump, but it starts
repeatedly, imme-
diately after stop-
ping.
Related information
11. Servicing the product
12. Starting up the product after standstill
Cause
The setpoint is set too high. The differ-
ence between the outlet pressure and
Yes
the inlet pressure must not exceed 3.5
bar (51 psi).
The maximum pressure has been ex-
Yes ceeded, the inlet pressure is higher
than 6 bar, 0.6 MPa (87 psi).
The maximum pressure has been ex-
ceeded. Equipment elsewhere in the
Yes system causes a high pressure at the
pump, for example water heater or de-
fective safety equipment.
Yes Dry running or water shortage.
Yes The inlet pipe is blocked by impurities.
The foot or non-return valve is blocked
Yes
in closed position.
Yes There is a leakage in the inlet pipe.
Yes Air in the inlet pipe or the pump.
The internal non-return valve is defec-
No tive or blocked in completely or partly
open position.
The tank precharge pressure is not cor-
No
rect.
Remedy
Reduce the pressure to a new setpoint
(maximum 3.5 bar (51 psi) + positive inlet
pressure).
Example: If the inlet pressure is 0.5 bar (7
psi), the maximum outlet pressure is 4 bar
(58 psi).
Check the inlet conditions.
Check the installation.
Check the water source, and prime the
pump.
Clean the inlet pipe.
Clean, repair or replace the foot or non-re-
turn valve.
Repair the inlet pipe.
Prime the inlet pipe and the pump. Check
the inlet conditions of the pump.
Clean, repair or replace the non-return
valve.
Adjust the tank precharge pressure to 70
% of the required outlet pressure.
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