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• 2 PIPE HEATING/C ELECTRIC RESISTANCE mode with SEASON CHANGEOVER
by PARAMETER (
M01
=7):
The season is chosen manually (see
“MODE button functionality” page 9):
Once you have made the selection, either “
HEAT
” or “
COOL
” is displayed, depending on the mode.
Heating regulation is controlled as follows for 2 pipe heating/cooling mode (
M01
=5, 6, 7):
The “
HEAT
” icon is on to indicate that heating mode is active.
The regulation logic is as follows:
100
0
Temp.
PBH
(
I22
)
Outputs
BHS
(
I07
)
AO1
ECM speed 1
% opening valve
Fan
ECM speed 3
(
I31
)
0%
100%
HH
(
I18
)
DIFF
(
I20
)
DO1
AO2
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 (output
AO2
) starts when the valve reaches the minimum aperture given by parameter
I31
, and after the fan
start delay
I36
has expired.
The speed increases linearly as the valve opens. Speed 3 is reached when the valve is fully open (see
“EC motor auto-
matic speed control logic with 0..10 V modulating outputs” page 28
).
If the temperature drops below
I07
-
I2.0
-
I18
the electric resistance output (
DO1
) is activated and icon
turns on.
If the temperature returns above
I07
-
I20
the electric resistance output is deactivated and icon
turns off.
A timer now starts (parameter
I35
) during which the fan cannot be turned off even if the setpoint is reached. Once delay
I35
has expired, the fan can be turned off if necessary.
When the electric resistance turns on, the fan turns on immediately regardless of the ventilation delay set in parameter
I36
and the position of the minimum thermostat (if in use).
Icon turns off when the valve closes again, in which case the fan stops 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. If, on the other hand, the electric resistance turns on, the fan starts immediately regardless
of the position of the minimum thermostat.
