Grundfos PHT-N130 Installation And Operating Instructions Manual page 41

13.0 Fault Finding Guide.
Fault Message Fault Condition
Service Required It has been more than 12 months since
the unit was last serviced.
Low Water The water in the break tank has fallen
below the Low Water Float Switch(DI1).
High Water The water in the break tank has risen
above the High Water Float Switch(DI2).
Low Glycol The glycol in the glycol tank has fallen
below the Low Glycol Float Switch(DI3).
Low Pressure The system pressure has fallen below the
[System Low Pressure Alarm ON] set
point.
High Pressure The system pressure has risen above the
[System High Pressure Alarm ON] set
point.
Pump Over The pump current has risen above the
Current pump full load current by the factor set
in the Engineers menu.
Pump Under The pump is not drawing sufficient
Current current.
Flood Protection The allowable pump run time in the past
hour has exceeded the [Flood Protection
Limit] set point.
(an excessive amount of water has been
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GRUNDFOS INSTRUCTIONS
Remedy
Arrange for an engineer to service the unit.
Once a full service has been performed, ensure
that the service date is reset.
Check the water supply to the unit and ensure
that the float valve is operating/set up correctly.
Once the water level has been restored, wait up
to 2 minutes for the fault to reset.
If the fault does not reset, check the function of
the Low Water Float Switch (DI1).
Check the water level in the tank.
Ensure that the float valve is operating/set up
correctly.
If the break tank is being back-filled from the
system, the pump non return valves should be
inspected for damage/debris.
Once the water level has been restored, wait up
to 2 minutes for the fault to reset.
If the fault does not reset, check the function of
the High Water Float Switch (DI2).
Add more glycol to the glycol tank.
If the fault does not reset, check the function of
the Low Glycol Float Switch(DI3).
Check that the isolation valve to the system is
open.
Check the pressure reading against a mechanical
gauge if one is available.
If the pressure needs to be increased
substantially, add more water via a filling loop.
Check that the isolation valve to the system is
open.
Check the pressure reading against a mechanical
gauge if one is available.
Check if the filling loops have been left open.
Drain water from the system via a suitable drain
point until the correct pressure is restored.
If the fault reoccurs, inspect the system
expansion vessel and check its pre-charge
pressure.
Test the operation of the pump by manually
operating the pump.
Overcurrent can indicate a worn/seized motor.
Service or replace the pump as required.
Check that the voltage supply to the unit is
within the specified limits.
Test the operation of the pump by manually
operating the pump.
Undercurrent can indicate damaged motor
windings (open circuit) or an air locked pump.
Check the Pump fuse has not blown.
Check that the voltage supply to the unit is
within the specified limits.
Service or replace pump as required.
Extreme water consumption can be caused by
very large leaks (Burst pipes, open drain valves,
etc.), work being done on the system (draining
of large parts of the system), or bleeding of
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