Fläkt Woods
3176 GB 05.08
6
Specifications are subject to alteration without notice
EU Air Handling Unit
MAINTENANCE
EUQA Humidifier, for circulated water
Chart 1
Zone 1 is the safe zone, in which the water is soft or
demineralized.
Zone 2 is the lower part of the transition zone, in which
the water can be said to be of normal drinking quality.
Zone 3 is the upper part of the transition zone, in which
the water is relatively hard.
Zone 4 is the precipitation zone, in which the water is
very hard. The water must be subjected to partial softe-
ning, so that its quality will be within zone 2–3.
However, the softening treatment must not lower the
quality of the water to zone 1.
Example
Data from the municipal water authority:
pH = 7.6
Bicarbonate
70 mg/l
Calcium
30 mg/l
From Chart 1, the operating point is in zone 1 (safe
zone).
Water consumption
The water consumption consists of the water evaporated
and a certain amount of water bleed-off. This bleed-off
flow is necessary to reduce the consumption of salts in
the circulating water. If the concentration of salts is too
high, salts may be deposited on the humidifier fill, which
will have a detrimental effect on the performance of the
humidifier.
The chart above can be used to determine the appropria-
te bleed-off flow.
If the humidifier has been sized for running over a long
period at a high humidification rate
∆
x above 8 grams per kg of air (90% humidifier) and
∆
x above 5 grams per kg of air (60% humidifier) respec-
tively is recommended if the water tray is emptied and
flushed twice a day. (See: To set the timer for emptying
and flushing.)
Periods out of service
The controller of the humidifier switches to the empty-
ing mode whenever the fan is switched out.
Clean the water tray if the system is to be shut down
for an extended period, such as during the annual holiday
and long weekends.
If the humidifier is to be out of service for some time,
the humidifier fills should be removed, cleaned and sto-
red in a place where they will not sustain damage.
10
10 000
6000
2000
4000
1000
600
400
200
100
60
40
20
10
6
4
2
1
5
6
7
8
9
8,5
9,5
4
2
6
20 40 60 100
1000
10 000
Calcium Ca
2+
mg/l
pH-value
Max. pH of aluminium
Bikarbonate HCO
3
–
mg/l
Precipitation zone
Transition zone
Safe zone