Technibel CAFP 124 R Technical Data & Service Manual page 85

Overcurrent protection control
(1) If the overcurrent protection circuit detects abnor-
mal current, the compressor is stopped. (Error
count = 1.) The compressor then restarts after 3
minutes.
(2) If compressor start/stop is repeated 4 times (error
count = 4), alarm "P26," "P29," or "H01" (count =
2 in this case only) occurs. Operation stops and
does not restart.
Current release value shift control
(1) This control is intended to improve compressor
reliability by preventing continuous high-frequen-
cy operation under overload conditions when the
outdoor air temperature is high, and by prevent-
ing intermittent operation through "control for pre-
vention of high cooling loads."
(2) The control value for "current release control" is
corrected according to the outdoor air tempera-
ture (TO).
Depending on the temperature, the control value
is lowered to 55 – 90% for cooling operation, and
to 85 – 98% for heating operation.
Freeze prevention (low-temperature release)
control
The below control is performed during cooling opera-
tion (including dehumidifying operation), using
whichever of the indoor heat exchanger temperatures
(E1 or E2) is lower. (See the figure below.)
(1) If a temperature in the "J" area (operating fre-
quency reduction and thermostat OFF area) is
detected for 6 minutes, the compressor operating
frequency is reduced.
The compressor operating frequency is reduced
every 30 seconds as long as the temperature
remains within this area.
(2) If the temperature is in the "K" area (operating
frequency increase-prohibit area), the compres-
sor operating frequency is maintained.
(3) If the temperature is in the "H" area (operating
frequency control area), and the outdoor air tem-
perature is less than 32°C, the compressor maxi-
mum operating frequency is limited according to
the indoor unit fan speed.
(4) If the temperature is in the "I" area (normal oper-
ating area), the compressors operate normally.
(5) If the temperature is continuously in the "J" area
and the compressor operating frequency reaches
0, then temperature A (temperature for changing
from "J" area to "H" area) is raised from 5°C to
12°C, and operation continues with the thermostat
OFF until the temperature reaches the "H" area.
Heating high-load control
The below control is performed during heating opera-
tion, based on the indoor heat exchanger temperature
(E2).
E1 (or E2) (°C)
22
17
5
2
(1) If the temperature is in the "M" area (operating
frequency reduction and thermostat OFF area),
the compressor operating frequency is reduced.
The compressor operating frequency is reduced
every 30 seconds as long as the temperature
remains within this area.
(2) If the temperature is continuously in the "M" area,
the thermostat turns OFF.
(3) If the temperature is in the "N" area, operating
frequency increases are prohibited.
(4) If the temperature is in the "L" area, the operating
frequency is raised to the original frequency (the
frequency prior to frequency reduction) by 6 Hz
every 60 seconds.
E1, E2 (°C)
(25 type) (36, 48 types)
58
65
52 (51)
56 (54)*
52
46
30*
*
When the compressor turns ON and the E2 tem-
perature rises, the temperature at which the "M"
area is first entered is 54°C (36, 48 types) or higher
than 51°C (25 type).
If the E1, E2 temperature subsequently falls to the
"L" area, the temperature for entering the "M" area
is raised to 56°C (36, 48 types) or 52°C (25 type).
However if the E1, E2 temperature falls to the "L"
area and falls below 30°C, then the temperature for
entering the "M" area is changed back to 54°C (36,
48 types) or 51°C (25 type).
2 - 3
I
H
A
K (operating frequency
increase-prohibit area)
J
Thermostat OFF
M
N
(operating frequency
increase-prohibit area)
L
2