Caution - Grundfos SCALA 2 Service Instruction

Fault
4. System
overpressure.
5. You can reset the
pump, but the
pump runs only for
a few seconds.
6. You can reset the
pump, but the
pump starts
repeatedly,
immediately after
stopping.
12
Cause
The setpoint has been set too high.
The difference between the outlet
pressure and the inlet pressure must
not exceed 4 bar (58 psi).
Yes
Example: If the required outlet
pressure is 5 bar (73 psi), the
minimum inlet pressure must be 1 bar
(14.5 psi).
The maximum pressure has been
Yes exceeded and the inlet pressure is
higher than 6 bar, 0.6 MPa (85 psi)
The maximum pressure has been
exceeded. Equipment elsewhere in
Yes the system causes a high pressure at
the pump (e.g. water heater or
defective safety equipment).
Yes Dry running or water shortage.
The inlet pipe is blocked by
Yes
impurities.
The foot or non-return valve is
Yes
blocked in closed position.
Yes Leakage in the inlet pipe.
Yes Air in the inlet pipe or the pump.
The internal non-return valve is
No defective or blocked in completely or
partly open position.
The tank precharge pressure is not
No
correct.
Remedy
Reduce the setpoint to 4 bar (58 psi)
plus positive inlet pressure.
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-return 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.