29
ENG
Heos +0300078EN - rel. 1.6 - 23.11.2017
d5
regulation
ONTIME = 0
OFFTIME = 0
regulation regulation
regulationdefrost
A
C
B
time
time
CMP
ON
OFF
CMP
ON
OFF
1
2
Fig. 6.v
Key
CMP Compressor
The purpose is to stop control and allow natural defrosts only when
necessary.
Skip defrost (parameters d7, dn, do)
The function applies to defrosts that end by temperature, otherwise it
has no eff ect. The Skip defrost function evaluates whether the defrost
duration is less than a certain threshold (dn) and based on this establishes
whether or not the subsequent defrosts will be skipped.
Par. Description Def U.M.
Min Max
d7 Enable skip defrost
0: disabled (NO); 1: enabled (YES)
0--01
dn Nominal defrost duration for skip defrost 45 min 0 240
do Number of defrosts to be performed when starting
before activating skip def.
7--19
The algorithm keeps a counter of the defrosts to be skipped:
• if the defrost ends in a time less than dn1, the counter of the defrosts
to be skipped is increased by 1;
• if the defrost ends normally, the next defrost is performed;
• when the counter reaches 3, three defrosts are skipped;
• at start-up, the defrost is performed “do” two times without increasing
the counter.
Power defrost (parameters ddt, ddP)
Power defrost is used to increase the end defrost threshold dt1 and/or
the maximum defrost duration dP1. These increases allow longer and
more eff ective defrosts. Power defrosts are performed on each defrost
call during night-time status or when suitably confi gured by the RTC
parameters (sub-parameter P of parameters td1 to td8), so as to allow
the user to choose the conditions that are most suitable for this special
procedure. Power Defrost is activated when at least one of the increases,
ddt or ddP, has any value other than zero.
Par. Description
Def U.M.
Min Max
ddt
Additional defrost temperature delta in Power
Defrost mode
0.0
(0.0)
°C
(°F)
-20.0
(-36.0)
20.0
(36.0)
ddP
Additional maximum defrost time delta in Power
Defrost mode
0 min 0 60
Note: in Power Defrost mode, the maximum defrost duration dP1
is increased by the value of parameter ddP.
6.8 Evaporator fans
The evaporator fans can be set to operate always, or be managed
according to the temperature measured by the defrost and control
probes. Fan behaviour is set by par. F0:
Note: 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 6, and an example of the trend based on the diff erence
between the evaporator temperature and the value of the virtual probe
(F0=1). If F0=2, activation depends solely on the evaporator probe
temperature.
Par. Description Def U.M. Min Max
F0 Fan management confi guration 0 -- 0 2
F1 Fan activation threshold -5.0
(23.0)
°C
(°F)
-50.0
(-58.0)
50.0
(122.0)
F2 Enable fans off with controller off (OFF); 0: see
F0; 1: always off
0--0 1
F3 Enable fans off during defrost
0: fans always ON
1: fans always OFF
2: fans ON, OFF in dd
0--0 2
Fd Fan Off time in post-dripping
0: no dripping
60 s 0 240
Frd Fan diff erential 2.0
(3.6)
°C
(°F)
0.1
(0.2)
20.0
(36.0)
dd Dripping time after defrost (fans off ) 120 s 0 600
time
Temp.
F1
ON
OFF
FAN
Sd-Sv
(F0 = 1)
Frd
Fig. 6.w
Key
Sd Evaporator probe Frd Control diff erential
Sv Virtual probe FAN Evaporator fans
F1 Fan activation speed setting
The fans can be turned off in the following situations:
• when the compressor is off (parameter F2);
• during 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.
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 a PWM or 0-10 V output. The maximum
and minimum fan speed can be set using parameters F6 and F7. Frd
in this case represents the variation in temperature for switching fan
speed from minimum to maximum. 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 Def U.M. Min Max
F5 Evaporator fan cut-off temperature
(hysteresis 1°C)
0.0
(32.0)
°C
(°F)
-50.0
(-58.0)
50.0
(122.0)
F6 Maximum fan speed 80 % min 100
F7 Minimum fan speed 10 % 0 max
F8 Fan peak time
0: function disabled (NO);
10 s 0 240
F9 Override fan output to 100% every:
0: function disabled (NO);
0 min 0 240
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