ADDITIONAL CONTROLS
EMERGENCY FUNCTIONING
The two following failure cases are fore-
seen when the thermostat operates in
the described manner.
NO WATER PROBE
- Ventilation is always active
- The season change is made on the basis
of the difference between the setting
made and the actual ambient tempera-
ture. If the ambient temperature exceeds
by a value equal to the dead band, the
Heating setpoint switches to the Cooling
mode. If the ambient temperature drops
by a value equal to the dead band below
VENTILATION CYCLES OF 2-PIPE SYSTEM WITHOUT AMBIENT PROBE
AMBIENT PROBE ABSENT (4 PIPES)
In this case the thermostat operates as
follows:
- OFF - Aux Mode
The valves are closed
The fan is off
- AUTO, V1, V2, V3 mode:
The operating season is decided accord-
ing to the position of the temperature
selector and it is activated by the respec-
tive valve as shown in the Figure
The ventilation in this case is always per-
formed according to the ON-OFF cycles,
however, increasing the ON phase from
the central position. In this way the maxi-
mum ventilation can be required with
the selector at the minimum position for
VENTILATION CYCLE OF THE 4-PIPE SYSTEM WITHOUT AMBIENT PROBE
the Cooling setpoint, it switches to the
Heating mode.
- The turning on/off of the resistance does
not depend in this case on the tem-
perature of the water but on the sheer
demand for the thermostat operation
AMBIENT PROBE ABSENT (2 PIPES)
In this case the thermostat operates as
follows:
- OFF - Aux Mode
The valve is closed
The fan is off
ON cycle
SetPoint
duration
Min value
Nil
20 C°
2'20"
5'20"
Max value
Minimum value
Cold water valve opening, ventilation
period proportional to the deviation
of the median position
cooling operation season and likewise
there is maximum ventilation with the
selector in the maximum position. For
the heating operation season. The total
duration of the ON-OFF cycle is again
5'20'' . The following table gives duration
ON cycle
Position
duration
5'20"
Min value
20 C°
Nil
5'20"
Max value
- AUTO, V1, V2, V3 mode:
The valve is always open.
Operating season always hot.
- The ventilation runs On-Off cycles. The
duration of the ON cycle is proportional
to the setpoint set in the VMF-E4 panel.
The total duration of the ON-OFF cycle
corresponds to 5'20'' . The following table
gives duration examples of various ON
and OFF cycles based on the position of
the temperature selector:
OFF cycle
duration
5'20"
2'60"
Nil
SETPOINT
Hot water valve opening, ventilation
period proportional to the deviation
examples of various ON and OFF cycles
based on the position of the tempera-
ture selector:
OFF cycle
duration
Nil
5'20"
Nil
Keys used to
modify the
setpoint value
Maximum value
of the median position
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