Functions
Additional functions
4
50 | 150
A6V11545892_en--_a
Set different limits to the flow in both sequences, heating and cooling to balance
heating and cooling systems and avoid hydraulic problems caused by the different
flow rates.
Cooling typically requires a higher flow rate than heating, and the combi valve
(PICV) is mechanically and manually set to the cooling flow limit.
However, when the system operates in heating mode, set another flow limitation.
The new limit to the DC 0...10 V signal (new 100 % heating demand) can now be
set with the parameter P256.
The function can be enabled on all combined heating/cooling applications with
DC 0...10 V output for universal and fan coil unit applications.
T[
℃
] Room temperature
Y10 DC 0…10 V signal
W Room temperature setpoint
YH Control command "Valve"
(heating)
YC Control command "Valve"
(cooling)
The function can be enabled for the following heating/cooling applications with
DC 0...10 V output. P256 is not visible on other applications.
Fan coil type
●
4-pipe with PICV and 6-port ball
valve as changeover
Universal type
●
H/C ceiling with PICV and 6-port
ball valve as changeover
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 [
To prevent valve freezing after extended inactivity (e.g. cooling valves in winter),
valves need to be activated periodically. To save energy, the valve 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.
Flow limitation function for
combi valve (PICV) (P256,
RDG260KN)
Dewpoint monitoring
Note
Fault state “condensation”
(P150 / P153 / P155 = 4)
Fault information
Valve exercising (P250)