Fast RCF Series, Manual

Page: 12 / 27

Heat recovery unit with cooling circuit - RCF -
0208-6180549-rev. 02
12
GB
Controls manual
Recording operating hours
The device stores the number of operating
hours for the following in the non-volatile
memory:
• evaporator fan
• compressor.
Internal resolution is in minutes.
The values can be displayed by accessing
the menu with the label Ohr (see menu
layout). The whole value is displayed for
values below 999 whereas hours/100 value
along with the decimal point is displayed for
values above 999.For example, 1234 hours
are displayed as follows:
The hours can be reset by pressing the
DOWN button for two seconds (see buttons)
while the operating hours are displayed.
In the event of a power failure, the last frac-
tion of hour recorded is set to 0 and the
duration is rounded off by default.
Defrosting
The defrost function is only active in Heating
mode.
This function is used to prevent the forma-
tion of ice on the surface of the external heat
exchanger.
This significantly reduces the thermodyna-
mic performance of the unit and could cause
it severe damage.
Defrosting is controlled according to pres-
sure.
Defrost start and stop commands are given
on the basis of condensation probe readings
and parameter settings, as described below.
Defrost mode start (fig. 01)
If the condensing pressure is lower than 3 bar
(defrost starting pressure) and the compressor
is ON, the control starts the defrost coun-
tdown (1 min countdown). When 1 min pas-
sed, the control device starts the defrosting
process. At this point Pad06 (compressor..
valve time delay) = 30 sec., the control proce-
dure described in fig. 01 is operated.
This delay prevents the compressor from
liquid returns. During this operation the
safety timings of the compressor are not con-
sidered. The defrost starting and stopping
pressures are the following:
• defrost start: 3 bar
• defrost stop: 10 bar.
Defrost mode stop (fig. 02)
The defrosting process stops if:
• the condensing pressure raises up to the
defrost stop pressure,
• the defrosting process doesn’t stop in 5 min
(max. defrosting time).
Counter mode
• The defrost time counter is interrupted
when temperature/pressure rises above Pa
d02 (defrost start temperature/pressure) or
the compressor is turned off.
• The counter is reset following one of these
events: defrost cycle performed; power failu-
re; change in operating mode.
• The counter is also reset when the tempe-
rature/pressure rises above Pa d04 (defrost
end temperature/pressure).
Power failure
If there is a power failure, when the power is
restored the control returns to the state prior
to the power failure. If defrosting is in pro-
gress, the procedure is cancelled. All timing
in progress is cancelled and restarted.
12.3
35.48 35
Pa d06
ON
OFF
ON
OFF
COMPR
RV
Pa d06
SD
COMPR: compressor
RV: reversing valve
SD: start of defrosting
fig. 01
Pa d07
ON
OFF
ON
OFF
COMPR
RV
Pa d07
FD
COMPR: compressor
RV: reversing valve
FD: end of defrosting
fig. 02