EVCO EPU2BXP1S1 - Manual (Page 48)

EVCO S.p.A. c-pro 3 micro SAVE/ c-pro 3 kilo SAVE | Application Manual ver. 1.0 | Code 144CP3UKSAE104
EVCO
page 48 of 68
6.7.2.1 Unit without By-pass damper
In this case the action taken for anti-freeze purpose is decreasing the fan speeds with a neutral zone control.
When T ≤ Tg, the outlet fan speed will decrease progressively (V3-V2-V1) until stopping (V0). If this condition occurs
and remains for a time ∆t (time set by parameter PF09) the speed reduction takes place, every ∆t there is a further
decrease until the supply fan switches OFF.
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).
6.7.2.2 Unit with motorised By-pass
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).
6.7.2.3 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.
Tg -
OFF
T. Anti- Tg +
ON
Dampe
r
Fan speed decrease
every
Neutral
Zone
Normal Working
Tg Tg + T. Anti-
freeze