77/126
The regulation logic is as follows:
Temp.
BHS
(
I07
)
PBH
(
I22
)
100
0
Output valve
speed 1
% opening
valve
Fan
speed 3
(
I25
)
0%
100%
speed 2
(
I26
)
(
I27
)
AO1
DO1
DO2
DO3
If the operating temperature drops below
I07
, the valve starts opening (output
AO1
). Icon turns on.
The valve can be regulated with PI action if the integral time
I24
is non-zero or with only proportional action if
I24
=0.
The fan starts when the valve reaches the aperture defined in
I25
and after startup delay
I36
.
If the temperature continues falling, the speed switches from speed 1 to speed 2 when the valve reaches the aperture
given in
I26
. The speed switches from speed 2 to speed 3 when the valve reaches the aperture given in
I27
.
Each speed is subject to a hysteresis of 20% of its activation point.
For example, for speed 3:
if
I27
=100%, speed 3 is activated when the valve reaches fully open and is deactivated when the valve closes by 20%
of
I27
, which is 80% of fully open in this case.
Icon turns off if the valve closes again, in which case the fan is stopped if
I28
=0 or 2. The fan maintains speed 1 if
I28
=1 or 3.
The fan maintains speed selected manually if
I28
=4 or 6.
N.B.: if the minimum thermostat function is active, the thermostat itself must be closed when the valve is in regulation,
otherwise the fan will not start.
