Carrier RAV-SP180UT-UL Service Manual page 43

No. Item
7 Cool air discharge
preventive control
8 Freeze preventive control
(Low temperature release)
Outline of specifications
1) In heating operation, the indoor fan is controlled
based on the detected temperature of Tc sensor or
Tcj sensor. As shown below, the upper limit of the
revolution frequency is restricted.
However B zone is assumed as C zone for
6 minutes and after when the compressor activated.
In defrost operation, the control value of Tc is
shifted by 42.8°F (6°C).
Tc, Tcj
˚F [˚C]
HH
89.6 [32]
H
86.0 [30]
L
82.4 [28]
UL
78.8 [26]
OFF
68.0 [20]
60.8 [16]
1) The cooling operation (including Dry operation) is
performed as follows based on the detected
temperature of Tc sensor or Tcj sensor.
When [J] zone is detected for 6 minutes
(Following figure), the commanded frequency is
decreased from the real operation frequency.
After then the commanded frequency changes
every 30 seconds while operation is performed in
[J] zone.
In [K] zone, time counting is interrupted and the
operation is held.
When [ I ] zone is detected, the timer is cleared
and the operation returns to the normal operation.
If the commanded frequency becomes S0
because the operation continues in [J] zone, the
return temperature A is raised from 41°F (5°C) to
53.6°F (12°C) until [ I ] zone is detected and the
indoor fan operates with [L] mode.
˚F [˚C]
41 [5]
35.6 [2]
In heating operation, the freeze-preventive control
works if 4-way valve is not exchanged and the
following conditions are satisfied.
(However the temperature for J zone dashing control
is changed from 35.6°F (2°C) to 23°F (–5°C.))
<Conditions>
Q R
• When or is established 5 minutes after
activation.
Q
Tcn ≤ Tc (n – 1) – 5
R
Tcn < Tc (n – 1) – 1 and Tcn ≤ Ta < 41°F (5°C)
– 43 –
E zone
D zone
C zone
B zone
A zone
I A
K
J
Remarks
In D and E zones, the
priority is given to air
volume selection setup
of remote controller.
In A zone while thermo
is ON, [PRE-HEAT
(Heating ready)] is
displayed.
Tcj:
Indoor heat exchanger
sensor temperature
Tcn:
Tc temperature when 5
minutes elapsed after
activation
Tc (n – 1):
Tc temperature at start
time