fisair DFRA Series, User Manual

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User Manual DFRA Series |
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12. Maintaining the desiccant rotor.
The desiccant rotor is the only component of the dehumidifier that needs special
attention.
The desiccant rotor fitted to these units does not require specific ongoing maintenance.
The speed of rotation is very slow, and the bearings and desiccant material are designed
for continuous operation. It is however very important to check the drive system on a
regular basis to ensure it is working correctly, as this has a direct impact on the air-drying
process.
The main constituent in the process of water vapour adsorption (silica gel) traps the water
vapour molecules inside the tiny pores (micropores and mesopores) on the rotor surface
in the process air circuit and releases them into the reactivation air circuit.
The operating process is not affected by normal ambient conditions as the rotor is made
from inert fireproof material. Only the presence of organic compounds with a molecular
size similar to that of water can affect the unit's drying capacity. It is therefore important
to clean it on a regular basis.
Procedure for washing the silica gel desiccant rotor
The desiccant rotor fitted to the unit has the advantage over a hygroscopic salt desiccant
rotor (Lithium Chloride) that it can be washed with water.
Normally, ordinary dust particles must be removed with a vacuum cleaner when
necessary. The frequency of cleaning will depend on the type of installation and workload
to which the dehumidifier is subjected.
In cases where the vacuum cleaning is insufficient to eliminate dust and dirt, the rotor
can be rinsed with water following these steps:
1) Remove the rotor from the dehumidifier. Disassemble its drive shaft and
bearings, which must be reinserted in their original position after they have been
washed.
2) Prepare water in a container that is large enough to immerse the rotor in for
washing and prepare the rotor so that it can be immersed by moving it vertically
downwards.
3) Immerse and remove the rotor from the water tank two or three times. Let the
water run off completely while it is held in a raised position so that any materials
that have been dissolved in the water are removed.
4) Once this process is complete, carefully blow the rotor channels with compressed
air to expel any remaining water on the rotor.
5) Return the rotor to its position in the dehumidifier, securing its drive shaft,
bearings, and sealing joints.
6) Turn the rotor and dry it with the fans without switching on the reactivation heater
for approximately 30 minutes.
7) Complete the rotor drying process by switching on the reactivation heater.