Vimar 02952 Installer Manual page 6

Thermostat
General characteristics and functions
Neutral zone
The "Neutral Zone" is an operating mode of the thermostat (only
for 4-pipe systems) in which the device keeps the temperature
within a temperature range preset by the Winter Setpoint
and Summer Setpoint (basically, there is no longer the usual
Summer/Winter mode).
If the measured temperature is below the Winter Setpoint, the
thermostat switches on the heating valve and heats the room until
the temperature exceeds the set value (e.g. 20°C for Comfort
mode or 18°C for Standby mode). If the measured temperature
exceeds the Summer Setpoint then the thermostat switches
on the cooling valve and keeps it on until the temperature falls
below the set Summer Setpoint value.
Within the Neutral Zone the thermostat does not switch on any
valves and the temperature can vary freely; this zone is therefore
nothing more than the difference between the Summer and
Winter Setpoints when the room temperature is between the
winter setpoint and the summer one.
To avoid excessive temperature fluctuations, set a limited range
(≤ 2°C) as shown in the figure below.
Summer Setpoint
Winter Setpoint
Setpoint displayed in Neutral Zone operation
When the thermostat is working in the neutral zone, the setpoint
used for the adjustment is always the Current Setpoint, namely
the one relating to the last heating/cooling mode that came into
operation; the value displayed is instead a new setpoint named
"Neutral Zone Setpoint", which is the average value between
the current summer and winter setpoints.
Changing the temperature of the "Neutral Zone Setpoint" (with
the "+" and "-" buttons on the thermostat) will also cause a
change to the value of the "Shift Setpoint" resulting in a shift
of the two current summer/winter setpoint values; the room
temperature will therefore not become the one set by the guest
but that of the summer/winter setpoint which at that moment
is closest to the value of the current temperature in the room.
Between the two summer/winter setpoints, there is the neutral
zone in which the system is not activated.
Configuration
6
COOLING
NEUTRAL ZONE
HEATING
The KNX 02952 thermostat is configured in Neutral Zone mode
if the following object is NOT connected: "Enable A: Summer -
Winter – control" or "Enable B: Summer - Winter – control".
The KNX 02952 thermostat can operate in Neutral Zone IF:
• The system has 4 pipes
• Winter Comfort Setpoint < Summer Comfort Setpoint
• Winter Standby Setpoint < Summer Standby Setpoint
• Winter Economy Setpoint < Summer Economy Setpoint
• Antifreeze < Too Hot
If these conditions are not satisfied, you can still commission
the thermostat; if there is an error while starting up, the device
will remain in "Protected" mode and an error message will be
displayed.
For example, the following picture shows error 2 which is
equivalent to Winter Comfort Setpoint ≥ Summer Comfort
Setpoint.
Types of errors at the time of configuration
Error No.
Selected 2-pipe system instead of 4-pipe
E1
system
Winter Comfort Setpoint ≥ Summer Comfort
E2
Setpoint
Winter Standby Setpoint ≥ Summer Standby
E3
Setpoint
Winter Economy Setpoint ≥ Summer Economy
E4
Setpoint
E5 Antifreeze ≥ Too Hot
N.B.
Errors E2, E3, E4 and E5 may also be displayed if the
thermostat is programmed in "4-pipe system" mode without
the neutral zone according to the type of Setpoint shown in the
table.
Description