EVCO c-pro micro SAVE - Manual (Page 38)

C-PRO MICRO SAVE APPLICATION MANUAL
Page 38
If the temperature T is between Tg and Tg + Tdiff (default 3°C, can be modified by parameter PF08)
the current speed is maintained. Only when the temperature T becomes T ≥ Tg + Tdiff the fan speed
returns to the normal condition (i.e. at the speed set by the user).
6.6.2.2 Unit with motorised By-pass (digital contact excited)
Same behaviour as in the previous case with speed reduction but never down to zero in order to
allow the air flow through the recovery heat exchanger before being eject. As the exhaust air is
warmer than the outside air the heat exchanger is “defrosted”.
When the supply fan is at minimum speed and the low temperature situation still remains for
∆
t minutes, the fan does not switch off but there’s a particular activation strategy of the recovery
heat exchanger By-Pass damper:
•
When T ≤ Tg - TdiffByPass (default 2°C, can be modified by PF10 parameter): opening of
the By-pass damper
•
When T ≥ Tg + TdiffByPass: closure of the By-pass damper.
The return to normal working condition (speed selected by the user and By-Pass closed) takes place
only when T ≥ Tg + Tdiff (default 2°C, can be modified by PF08 parameter).
6.6.2.3 Recovery heat exchanger by-pass damper logic
The by-pass damper can be controlled using a digital signal or an analogue signal, it must be
configured setting the PG03 parameter from the manufacturer menu.
PG03=0
The damper is managed with a digital control via the DO7 relay. When the relay is not active the
damper is closed while when the relay is active the damper is open and the recovery heat exchanger
is by-passed.
PG03=1
The damper is managed with an analogue control via the analogue output AO3. When 0% the
damper is closed, while when 100% the damper is open and the recovery heat exchanger is by-
passed.
6.6.3 Cross flow recovery heat exchanger and by-pass damper
The recovery heat exchanger to be used is the cross flow static type. The anti-freeze by-pass damper
can be present in the unit (optional, the presence is determined by the status of digital input 5).
This damper allows the unit to work with very low outside air temperatures (e.g. –10 / -12°C)
preventing the moisture of the ejected air to condensate and freeze inside the heat exchanger (which
would cause the obstruction of air flow up to complete block).
The anti-freeze temperature probe identifies the freezing temperature and drives the fan speed
decrease and the activation of the recovery heat exchanger by-pass damper.
The recovery heat exchanger is normally active and is by-passed (opening the by-pass damper) only
during free-cooling (if present and enabled) and during cyclical defrosting when outside
temperature is too low. To activate this function set PG06 = 2
Tg - TdiffByPass
OFF
T. Anti-freeze Tg + TdiffByPass
ON
Damper
By-Pass