OPERATION AND MAINTENANCE MANUAL
Wall Mounted 0121…0661
16 (32)
Monobloc Wall Mounted Unit - WMA/WMF 0121-0181-0251-0281-0331-0551-0661 - Rev. 2.0. - Date: 18-07-2000 EN
SETTING THE AIRFLOW SENSOR
The FS differential pressostat should intervene if the fan is not working (if the unit has one fan only) or if one of the
fans is not working (in the case of multiple fans).
The setting of the airflow differential pressostat is 1.0 mbar (100 Pa). Since the difference in pressure between the
fan intake and delivery depends on the airflow, it is necessary to set the pressostat after installation, making sure
that the contact closes when the fan is in normal operation. To set the pressostat:
•
simulate a fan fault (stop the fan, or one of the fans if multiple); check that the pressostat intervenes
•
if the pressostat does not intervene, gradually
increase
the setting until it does.
The FS differential pressostat can be set on a scale from 0.5 to 5.0 mbar (from 50 to 500 Pa).
SETTING THE OPTIONAL DIRTY FILTER SENSOR
The PFS pressostat must be set as a function of the pressure drop; this depends not only on how dirty the filter is
but also on the airflow and therefore on the setting of the fan speed regulator. The setting must be done when the
filter is clean:
- set the PFS pressostat to 1.5 mbar;
- gradually cover the surface of the air filter and check that the pressostat intervenes when the filter is about 50-
60% covered
If the pressostat does not intervene, gradually lower its setting; if it cuts in too soon, increase the setting.
