Calculating The Room Temperature; Room Temperature Control Point; Heating/Cooling Mode; Anti-Freezing Mode - Carrier PRO-DIALOG PLUS 50AZ Installation, Operation And Maintenance Instructions

5.4 - Calculating the room temperature

Up to 2 sensors (1 of which is optional) may be used for cal-
culating the room temperature. Depending on the configura-
tion (see section 4.3.11.3), room temperature is either
calculated as the average of all readings, or is taken from the
minimum or maximum reading.

5.5 - Room temperature control point

The room control point associated with the active dead band
gives the room temperature which the unit must maintain.
Room temperature control point = Active room temperature
setpoint + offset.
The controller maintains room temperature at one of the
following levels:
• room temperature control point + [active dead band]/4 in
cooling mode, or
• room temperature control point - [active dead band]/4 in
heating mode.
5.5.1 - Active room temperature setpoint - Active dead
band
ACTIVE ROOM ACTIVE
TEMPERATURE SETPOINT DEAD BAND
Room temperature setpoint
- occupied mode Occupied dead band
Room temperature setpoint
- unoccupied mode Unoccupied dead band No
Anti-freezing setpoint 0°C (hysteresis 1.5°C)
The above setpoints can be changed in the Setpoint menu.
5.5.2 - Offset
An offset means that the active room temperature setpoint is
altered in line with external parameters. This may be carried out
in one of the following ways:
• By the user with the aid of an adjustment slider located on
the main T-56 room temperature sensor (which is
optional). The offset range is ± 3 K in increments of 1 K.
• Automatically in cooling mode, by reference to the outdoor
temperature (if the function has been validated in the
Configuration menu). In this case, the function is generally
used to limit the difference between the indoor and outdoor
temperatures in order to prevent thermal shock.
IMPORTANT: It is not possible to use both types of offset at
the same time. If the offset from the T-56 sensor is non-zero,
offset based on the outdoor temperature is ignored.
5.5.3 - Smart Start
This mode permits heating or cooling the room before it is occu-
pied so that the room temperature has reached its setpoint at the
beginning of the occupied period. The control calculates an antici-
pated start-up value in minutes, based on a user configurable
factor (anticipated start-up factor expessed in minutes/degrees
that must be adjusted for the installation) and the difference
between the setpoint and the room temperature. The higher the
anticipated start-up factor or the higher the setpoint difference,
the earlier the change-over to occupied mode is anticipated.
However, the start-up cannot be anticipated by more than 60
minutes.

5.6 - Heating/cooling mode

Units with heat pumps or additional heating stages may operate
in either heating or cooling mode.
•
•
The controller uses a hysteresis equal to the active dead band
divided by two. This means that the unit switches to ventilation
mode (i.e. forced air without heating or cooling) when:
•
•
•
•
Occupied Anti-freezing
mode? protection
Yes -
Disabled
No Validated

5.7 - Anti-freezing mode

The unit may be configured to be in anti-freezing mode when in
unoccupied mode (Configuration menu). In this case the fan is
shutdown and is only authorised to restart if room temperature
falls below the anti-freezing setpoint. It shuts down again when
room temperature is 1.5 K above the anti-freezing setpoint.
Selecting anti-freezing protection does not affect how the unit
operates in occupied mode. Anti-freezing mode for unoccupied
periods has to be selected in the Configuration menu.
Cooling mode is active when:
room temperature is above: room temperature control
point + [active dead band]/2
Heating mode is active when:
room temperature is below: room temperature control
point - [active dead band]/2
The unit has all its heating or cooling stages shut down and
room temperature is in the range: room temperature
control point - [active dead band]/2, and room tempera-
ture control point + [active dead band]/2.
The unit is in cooling mode and room temperature falls
below the room temperature control point.
The unit is in heating mode and room temperature rises
above room temperature control point.
The unit is part of a master/slave assembly. The master
unit is in cooling mode when the slave unit is in heating
mode and vice-versa. In this case the slave unit switches to
ventilation mode.
Room control point
Dead band
Heating mode
Standby mode
Active mode start point
Active mode end point
Room
Standby mode
temperature
Cooling mode
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