Basic Documentation

Functions
Additional functions
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Dewpoint monitoring is essential to prevent condensation on the chilled ceiling
(cooling with fan disabled, P350 = 0) and associated damages to the building.
A dewpoint sensor with a potential-free contact is connected to multifunctional
input X1, X2 or U1. If there is condensation, the cooling valve is fully closed until no
more condensation is detected, and the cooling output is disabled temporarily.
If the fan function is enabled (P350 ≠ 0), the fan continues to work as long as the
dewpoint function is active.
When condensation is detected with
● Control only with 6-port control ball valve:
– If P201 = 6 or 8, the valve closes (5 V).
– If P201 = 7 or 9, the valve closes (6 V).
● Control with combi-valve (PICV): The PICV closes and the 6-port ball valve
remains open.
The condensation symbol is displayed during temporary override and fault
"Condensation in room" is sent via bus.
The input must be commissioned accordingly (P150, P153 and P155).
See Multifunctional input, digital input [➙ 104].
To prevent valve freezing after extended inactivity (e.g. cooling valves in winter),
valves need to be activated periodically. To save energy, the valve kick/exercising
function is triggered when valves are closed for 91 hours. The valves are then
activated for 2 minutes. This function can be enabled via P250.
For district heating systems, this function is used to increase the system efficiency.
It guarantees that the delta temperature between flow and return temperature for
water does not drop below the defined setpoint selected by P061 for heating and
P062 for cooling.
As a result, the water flow and speed are reduced with a consequent reduction of
noise and of energy consumption.
● When the multifunctional input P150, P153 or P155 is set to 14 (Coil return
temperature), the parameters P061 (Setpoint ΔT cooling) and P062 (Setpoint
ΔT heating) are visible.
● Set P061 or P062 or both to the requested value to activate the return flow
temperature control function
Applications with flow and return temperature sensors are wired directly to the
thermostat:
Function
Multifunctional inputs P150, P153, P155
Sensor 1
Flow temperature
1)
= 12 (Coil flow temperature)
Flow temperature and changeover
2)
= 2 (H/C changeover)
Sensor 2
Return temperature
= 14 (Coil return temperature)
1)
(P15x = 12) If the flow temperature value is provided via KNX, the corresponding
multifunctional input setting (= 12) must be removed.
2)
(P15x = 2) The sensor temperature value is used for the changeover function
and flow temperature. If the thermostat receives the flow temperature value from
the bus, the thermostat works according to the flow value provided via bus (bus
has higher priority).
To receive the flow temperature via bus from a Synco device, set the same value
for distribution zone heating / colling (P903…P905) of the Synco device and
thermostats.
For an accurate delta temperature control performance, we recommended using
the same cable type and length for both flow and return sensors.
Dewpoint monitoring
Note
Fault state "condensation"
(P150 / P153 / P155 = 4)
Fault information
Valve kick/exercising
(P250)
Note
Note
Setting
Return flow temperature
control (P061/P062)