Evaporator Fans - Carel MPXPRO User Manual

Staggered defrosts
The function is used to perform a series of daily defrosts by setting just
the fi rst using parameter td1 and then indicating the number of defrosts
per day using parameter d1S. The controller automatically schedules
all the defrosts to be performed at regular intervals over the 24 hours
following the event defi ned by td1. The same applies to td2 and dS2.
Par Description
d1S Number of daily defrosts (td1)
0 = Disabled
1 = 24 hours 0 mins 8 = 3 hours 0 mins
2 = 12 hours 0 mins 9 = 2 hours 40 mins
3 = 8 hours 0 mins 10 = 2 hours 24 mins
4 = 6 hours 0 mins 11 = 2 hours 11 mins
5 = 4 hours 48 mins 12 = 2 hours 0 mins
6 = 4 hours 0 mins 13 = 1 hour 0 mins
7 = 3 hours 26 mins 14 = 30 mins
d2S Number of daily defrosts (td2)
see d1S
Remember that sub-parameter "d_" of td1(td2) defi nes the defrost day,
as follows:
d_ = Defrost– day
0 = event disabled
1 to 7 = Monday to Sunday
8 = Monday to Friday
Note:
• if event td1 includes a series of days, the programming always ends
at 24.00 on the last day. If event td1 includes one day only, the
programming ends at 24.00 on the same day;
• if both td1 and td2 are set, when the defrost events overlap, only the
sequence of defrost that start fi rst are performed.

5.7 Evaporator fans

The evaporator fans can be managed, if required, according to
the temperature measured by the defrost and control probes. The
deactivation threshold is equal to the value of parameter F1, and the
hysteresis is equal to the value of Frd.
Note: during the dripping waiting time (in the event of network
defrosts), and during the dripping time and post-dripping time, if
set, the evaporator fans are always off .
Fixed speed fans
Below are the parameters involved in managing fi xed speed fans, related
by default to relay 4, and a example of the trend based on the diff erence
between the evaporator temperature and the value of the virtual probe
(F0=1). If the double thermostat function is enabled, activation is based
on the diff erence between the evaporator temperature and the outlet
probe temperature.
If F0=2, activation depends solely on the evaporator probe temperature.
Par. Description
F0 Evaporator fan management
0 = always on
1 = activation based on Sd – Sv
(or Sd - Sm in double thermostat)
2 = activation based on Sd
F1 Evaporator fan activation threshold
(only if F0 =1 or 2)
Frd Fan activation diff erential (including
variable speed)
Def Min Max UoM
0 0 14 -
0 0 14 -
Tab. 5.u
9 = Monday to Saturday
10 = Saturday to Sunday
11 = every day
Def Min Max UoM
0 0 2 -
-5.0 -50.0 50.0 °C/°F
2 0.15 20 °C/°F
Tab. 5.v
F1
F1-Frd
ON
FAN
OFF
F1
F1-Frd
ON
FAN
OFF
Key
Sd Evaporator probe
Sv Virtual probe
F1 Fan activation threshold
The fan can be turned off in the following situations:
• when the compressor is off (parameter F2);
• during the defrost (parameter F3).
During the dripping period (parameter dd > 0) and the post-dripping
period (parameter Fd > 0) the evaporator fans are always off .
This is useful to allow the evaporator to return to temperature after
defrosting, thus avoiding blowing warm hot and moist air into the
refrigerated environment.
The evaporator fans can be forced on during control (parameter F2) and
during defrost (parameter F3).
Par. Description
F2 Evaporator fans with compressor off
0 = see F0; 1 = always off
F3 Evaporator fans during defrost
0 = on; 1= off
dd Dripping time after defrost (fans off )
0 = no dripping
Fd Post dripping time after defrost (fans
off with control active)
Variable speed fans
The installation of variable speed fans may be useful in optimising energy
consumption. In this case, the fans are powered by the mains, while the
control signal may come from:
• output PWM2 on the main board;
• a 0 to 10 Vdc output on the driver board.
The maximum and minimum fan speed can be set using advanced
parameters F6 and F7.
If using the fan speed controller, F5 represents the temperature below
which the fans are activated. There is a fi xed hysteresis of 1°C for
deactivation.
Par. Description
F5 Evaporator fan cut-off temperature
(hysteresis 1°C)
39
ENG
Sd-Sv
F0 = 1
t
t
Sd
F0 = 2
t
t
Fig. 5.p
Frd Diff erential
t Time
FAN Evaporator fans
Def Min Max
1 0 1
1 0 1
2 0 15
1 0 15
Tab. 5.w
Def Min Max
50 F1 50
Tab. 5.x
MPXPRO - + 0300055EN rel. 1.1 30/08/10
UoM
-
-
min
min
UoM
°C/°F