
The pH value measured during production was lower than the
specified minimum pH value for the delay time.
System response: “A. System response at too low a value”
Chapter 8.2.9 ‘Response of the system’ on page 57
Causes:
n
The pH value measurement is not correct. Recalibrate.
n
The caustic metering pump is not working - vent the liquid end.
n
The caustic concentration is incorrect. Check the conductivity
(mS).
n
The injection valve is dirty or blocked.
n
The pH value of the supply water has changed.
The pH value measured during production was higher than the
specified maximum pH value for the delay time.
System response: “B. System response at too high a value”
Chapter 8.2.9 ‘Response of the system’ on page 57
Causes:
n
The pH value measurement is incorrect. Recalibrate.
n
The analogue control of the caustic metering pump is not
working properly.
n
The caustic concentration is incorrect. Check the conductivity
(mS).
n
The pH value of the supply water has changed.
The air flow in the exhaust air duct for the hydrogen is too low
while the fan is running.
Causes:
n
The exhaust air duct is blocked.
n
The air flow sensor is incorrectly set.
n
The fan is faulty.
The air flow sensor does not switch off after the fan has been idle
for ≧ 2 minutes.
Causes:
n
The air flow sensor is faulty.
n
The air flow sensor is incorrectly set.
A thermal fault has occurred on the fan.
Causes:
n
The fan is operating under excessive load.
n
An electrical line to the fan is faulty.
8.2.4 Product tank
The level in the product tank is higher than the level switch.
System response: The product tank is switched off.
pH too low
pH too high
Air flow too low
Air flow sensor faulty
Thermal overload relay on fan
Level in product tank too high
[ALARM] / Troubleshooting menu
54