Fault Finding - Grundfos 189 Notice D'installation Et De Fonctionnement

5. Fault finding

Fault Cause
1. The gas dosing system is leaky. The
vacuum required for the change-over
function cannot be generated.
Changing over does
not work.
2. The diaphragm (fig. 15, pos. 51.26)
or O-ring (fig. 15, pos. 51.14) in the
change-over device are leaky.
1. The vacuum regulator (fig. 3, pos. 3)
lets through only an insufficient
amount of gas or the vacuum line is
too long (this fault occurs mainly with
a high flow rate).
2. The supply battery is frozen up.
The change-over
device switches to
the standby battery,
3. The change-over device is used in
although the supply
connection with the VGA 111 vacuum
battery is full and the
regulator with flow restricting nozzle,
connecting valve is
which limits the flow rate to max.
open.
600 g/h or 30 PPD. If the flow rate of
the gas dosing unit exceeds this
value, the vacuum increases and the
change-over device switches over to
the standby battery.
Discernible from
The variable area flowmeter (fig. 3,
pos. 9) indicates a flow, although
the supply battery (cylinder, drum)
is empty or closed.
The variable area flowmeter (fig. 3,
pos. 9) indicates a flow, although
the supply battery (cylinder, drum)
is empty or closed.
Measure the vacuum between the
change-over device and the
vacuum regulators with a vacuum
meter. The vacuum exceeds 2 m
WC (78" WC).
Measure the vacuum between the
change-over device and the
vacuum regulators with a vacuum
meter. The vacuum exceeds 2 m
WC (78" WC).
Remedy
Check the dosing system for
leaks. See section 4.2 Checking
the tightness.
Replace the defective parts.
Clean the vacuum regulator and
restart it or lay a vacuum line
with a larger cross section.
If the supply battery is frozen,
defrost it.
Measure the vacuum.
The vacuum must be less than
2 m WC (78" WC).
Reduce the flow rate.
If the maximum flow rate is
required, remove the flow
restricting nozzle in the vacuum
regulators or add further
vacuum regulators with drums
or cylinders to the system.
Measure the vacuum.
The vacuum must be less than
2 m WC (78" WC).
9