6.8 Possible Faults - Grundfos VGA-113-110 Installations- Und Bedienungsanleitung

6.8 Possible faults

Fault
Gas leakage at the pressure
connection.
Gas escapes at the overpressure line.
Formation of ice on the gas cylinder.
Desired dosing flow is not reached.
Despite correctly displayed gas flow the
desired gas solution concentration
cannot be reached.
Servomotor does not run.
The ball in the measuring tube is
caught.
Water in the measuring tube.
Servomotor does not reach the whole
desired range.
Servomotor runs in wrong direction.
20
Cause
The gasket at the pressure connection is
damaged.
Sealing surfaces are dirty, there are rests of
old gaskets on the sealing surfaces.
The sealing surface at the connection of the
gas cylinder is damaged.
The pressure connection is loose.
The sealing surface at the pressure connection
of the device is damaged.
Re-liquefacted gas enters the inlet valve.
The inlet valve is soiled or damaged.
The extraction amount per hours is higher than
1 % of the contents of the gas cylinder, the
system is too small.
The extraction amount per hours is higher than
1 % of the contents of the gas cylinder, the
system is too small.
Insufficient injector vacuum.
Leakage in vacuum line between dosing unit
and injector.
Vacuum line between dosing unit and injector
is too long.
Vacuum line is dirty.
The valve of the gas cylinder is closed.
The gas cylinder is empty.
Filter at the pressure connection of the dosing
unit is soiled.
Wrong adjusting spindle (diameter too low).
Leakage in vacuum line between vacuum
regulator and dosing unit.
Servomotor is switched to manual operation.
Measuring tube and/or ball are soiled.
Non-return diaphragm of the injector is
defective.
The servomotor or the control device is
adjusted wrongly.
The servomotor or the control device is
adjusted wrongly.
Correction
Replace the gasket.
Clean the sealing surfaces.
Use a different gas cylinder.
Tighten the pressure connection.
Call the service
Reduce the extraction amount, ensure
correct course of temperature.
Call the service
Use a dosing system with more than one gas
cylinders.
Call the service
Check the injector, repair it if necessary.
Observe the manual of the injector.
Check the motive water pump, repair it if
necessary.
Check the dirt trap before the injector, clean
it if necessary.
Eliminate the leackage.
Observe table "Suggested line lengths and
diameters".
Replace the vacuum line.
Open the valve of the gas cylinder.
Replace the empty gas cylinder by a new
one.
Call the service
Call the service
Eliminate the leakage.
Switch servomotor to automatic operation.
Call the service
Call the service
Call the service
Call the service