34
Thermostat
FAQ
23. Is it possible to control an On/Off type radiant heating
system and a fan coil air-conditioning system with 3
speeds?
You have to work prevalently with the thermostat object
"
Enable Summer/Winter
" (object 19). Firstly, the type of sys-
tem must be 4 pipes On/Off. Next, configure all the standard
datapoints required by the thermostat to operate correctly.
Add the following groups:
group 1
"Enable - Summer/Winter": to perform the season change
on the thermostat and disable the 3 speeds:
• "
Speed V1 - Disable fan
" (object 49)
• "
Speed V2 - Disable fan
" (object 50)
• "
Speed V3 - Disable fan
" (object 51)
• "
Status - Summer/Winter
" (object 18)
group 2
To operate the radiating system with On/Off valve in winter:
• "
Heating valve - valve
" (object 35)
• "
Relay
" (the relay of the device controlling the underfloor
system valve)
Note
: you can add to the group the object "
Fan coil: Disable
Local Operation
" (object 57) to disable the user interface of
the fan coil during the winter season.
group 3
To operate the fan coil general On/Off valve in the summer:
• "
Cooling valve - Valve
" (object 34)
• "
Relay
" (the relay of the device controlling the fan coil valve).
group 4
To control the fan coil speed V1 in summer:
• "
Relay
" (the relay of the device controlling the speed-1 of
the fan coil)
• "S
peed V1 - Fan Outputs
" (object 46).
group 5
To control the fan coil speed V2 in summer:
• "
Relay
" (the relay of the device controlling the speed-2 of
the fan coil)
• "S
peed V2 - Fan Outputs
" (object 47).
group 6
To control the fan coil speed V3 in summer:
• "
Relay
" (the relay of the device controlling the speed-3 of
the fan coil)
• "S
peed V3 - Fan Outputs
" (object 48).
In this configuration, when the thermostat is in Winter mode,
group 1
goes to "1" so the fan coil speeds are forcibly dis-
abled to block their operation and the thermostat operates
in On/Off only on the radiant heating valve as it is configured
for 4-pipe On/Off systems with
group 2
; in Summer
group
1
goes to "0" and the 3 speeds can again be controlled
from the bus; furthermore, the thermostat will operate with
the general fan coil cooling valve of
group 3
. The
Groups
4, 5
and
6
are those of the 3 speeds and objects 46, 47,
48 for the thermostat and they can be controlled from the
thermostat when the first group goes to "0" by setting the
thermostat in summer mode.
24. What objects are used to read the thermostat tempera-
tures from the Well-Contact Suite software?
For thermostats 02952, objects 10 and 11 (weighted aver-
ages of the temperatures that can be associated) are used
to read respectively the current temperatures of thermostats
A/B, and not objects 0 and 9 of the device (which are the
precise measurement data for the individual internal/external
probes).
25. Is it possible to eliminate the adjustment range in
Comfort mode, which can be expanded at the most to ±
5°C?
It is possible by setting the parameter "Guest Control
Permitted" onto "No Limitation".
26. If a 0-100% proportional fan coil rather than a three-
speed fan coil is controlled, will values 0-100% be sent
to the fan coil?
Yes, if the "Type" fan parameter is selected on "Proportional
(0-100%)".
27. How is the "
Dewpoint
" object used?
This object is used in systems with underfloor cooling and
is associated with a KNX humidistat capable of detecting
a level of humidity at which condensation may form on
the floor. By activating the ETS group for this object, the
thermostat will automatically go to "Off" mode, stopping air
conditioning.
It is possible to set a time limit after which the thermostat will
automatically go to "Off" if a message has not arrived from
the KNX humidistat. This operation does not occur in heating
mode.
28. How does the "
Comfort
" object work?
If "1" is sent to this object, the thermostat goes to "CMF"
mode (unless the window has been opened in the event of
window-contact control); if "0" is sent the thermostat goes to
"Standby" mode
29. IS it possible for a thermostat to control a 0-100% pro-
portional valve and an On/Off valve simultaneously?
No, it is not possible as setting the thermostat for propor-
tional control disables On/Off control on the valve object.
With two-zone thermostats (02952, 20430 and similar), it
is possible to operate "Thermostat-A" in one mode and
"Thermostat-B" in the other, but the guest would have to set
both each time to activate both the proportional valve and
the On/Off valve.
30. Can the thermostat be controlled from supervisors such
as the KNX touch screen?
Yes, the thermostats are KNX standard so a KNX certified
supervisor is capable of managing them.
31. If the parameter "
Enable menu
" is enabled (it is disabled
by default), what happens to the thermostat?
It enables the thermostat mode to be altered by acting on A
and B. On thermostats 02952 the "Enable Menu" parameter
is enabled by default.
32. How can operations performed by the guest on the
thermostat (change of temperature and functions) be
inhibited?
Using the objects "
Temperature: Disable Local Operation
"
and "
Fan coil: Disable Location Operation
" (objects 56, 57
and 103, 104) you can block changes to fan coil temper-
ature and speed. It is not possible to block the operating
