OUMAN EH-105, User Manual

Page: 26 / 60

In blast air temperature control, an attempt is usually made to utilise ”free energy”
as much as possible. The diagrams below illustrate a typical order for controls
in a heating situation (upper diagram) and cooling situation (lower diagram). The
cascade control system can be changed, see the following page.
EH-105 PRINCIPLE OF CASCADE CONTROL EH-105
Select
Mainten.mode
CascadeCtrlSyst
Cascade control when the heating need increases:
Open
Shut
Phase 2: Phase 3:
The control damper
is driven to recircu-
lated air. When the
damper is at the min
fresh air position
phase 3 begins.
Control of
heating unit
When the unit is
open phase 4
begins
Phase 4:
Air handling
output is decreased
(rotation speed)
to the set minimum
output.(Taking into
use p. 29)
Cascade control when the cooling need increases:
Phase 1: Phase 2:
Phase 3:
Mechanical cooling
HRU
HEATING
COOLING
DAMPERS
HRU
HEATING
COOLING
FAN CONTROL
DAMPERS
The cooling output (0…10V) is
controlled if:
1. The outdoor temperature is
higher than the set cooling
inhibit set value (
)
and
2. The room temperature is
higher than the room
temperature setting by the
amount of the heating/cooling
hysteresis and
3. The heating output is at 0.
"Outd.inhibit”
26
Open
Shut
Open
Shut
Open
Shut
Open
Shut
Open
Shut
Open
Shut
Open
Shut
Open
Shut
Open
Shut
FAN CONTROL
The HRU is driven
open. When the
HRU is at
maximum output
phase 2 begins.
Minimum limit during heating
Phase 1:
Cooling begins from
Phase 1 only if
”
” has
been selected. If it is
warmer outside than
inside, the HRU output
is increased if ½ of the
amount of the set
hysteresis between
cooling and heating has
been realised. When the
HRU is at max output
phase 2 begins.
Rev.Summer F
Minimum limit during cooling
Phase 2 begins only if
damper cascade control
and ”
” have been
selected. If it is warmer
outside than inside, the
damper sequence drives
the dampers to the min.
fresh air position of the
cooling period, if at least
½ of the amount of the
set hysteresis between
cooling and heating has
been realised. When
the dampers are at the
minimum fresh air
position of the cooling
period phase 3 begins.
Summer function
Reverse
Instr.
p.23