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5.7.4 Maximum Level Hygrostat (safety device)
Basically a simple on/off hygrostat is used as a maximum hygrostat. As usual it is connected to the safety circuit
(terminals L1 + H). Please also refer to the wiring diagram of the AT 3000 unit.
5.7.5 Humidity sensors with double units
The two cylinders of a double unit either can be run together (in parallel) or controlled separately from each other.
If both cylinders are controlled in parallel, only one humidity sensor is needed. When the two cylinders are controlled
independently, then each side requires a humidity sensor.
In the operating mode 2 a sequential operation can be realised. In this case the first cylinder runs to its full capacity,
once it is reached the second cylinder will start.
5.7.6 Upgrade
A later modification of already existing AT 3000 units with the integrated humidity controller is possible. The fitted
EPROM on the supply and processor pcb of the unit has to be replaced by the EPROM version XP16B or higher.
Before the replacement of the EPROM it is advisable to note down the changed parameters in the program level.
Then replace the old EPROM with the version XP 16B or higher. Afterwards do a Master Set (function 99 in the
program level) and then, if necessary, reprogram the original settings according to your requirements.
This procedure guarantees that no set parameters will be lost.
6. Rectifying faults
6.1 The humidifier produces insufficient or no steam
When a fault occurs, the problem is often sought only on the humidifier, though the fault may have been caused by a
problem in the plant.
For successful trouble-shooting, some knowledge of plant technology (air-conditioning, controls) is necessary.
You should proceed in the following order:
• Observe
• Work out the problem
• Take action
The following causes are possible:
• The steam cylinder is new and merely in the start-up phase.
• The humidistat/humidity controller is not demanding any humidity.
• A safety element, such as a maximum humidistat etc., is not allowing humidification to take place.
• The safety link between terminals L1 and H has not been made (if a proportional adaptor is used).
• The control fuse F1 or F2 has blown.
• The heating power is off or the electrode plugs have not been inserted.
• There is no water in the steam cylinder because the water supply has been interrupted (e.g. stop cock is closed etc.).
• The filter or the nozzle in the inlet valve is blocked or damaged.
• An output limitation has been programmed.
• The cylinder needs replacing.
• The humidifier is too small for the job.
• The current transformer is either defective or not connected correctly.
• The contactor coil is defective.
• The steam hose is blocked or has a kink in it.
