Carrier 38QUA009DS, Service Manual, Page: 83 / 116

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15.3.5 Inverter module protection
The Inverter module has a protection function
about current, voltage and temperature. If these
protections happen, the corresponding code
will display on indoor unit and the unit will stop
working.
15.3.6 Indoor fan delayed open function
When the unit starts up, the louver will be active
immediately and the indoor fan will open 10s
later.
If the unit runs in heating mode, the indoor fan
will be also controlled by anti-cold wind
function.
15.3.7 Compressor preheating functions
Preheating permitting condition:
If T4
＜
3
℃
(37.4°F) and the machine connects
to power supply newly within 5 seconds or if T4
＜
3
℃
(37.4°F) and compressor has stopped for
over 3 hours, the compressor heating cable will
work.
Preheating mode:
A weak current flow through the coil of
compressor from the wiring terminal of the
compressor, then the compressor is heated
without operation.
Preheating release condition:
If T4
≥5 ℃
(41°F) or the compressor starts
running, the preheating function will stop.
15.3.9 Condenser high temperature T3
protection
---55°C(131°F)<T3<60°C(140°F), the
compressor frequency will decrease to the
lower level until to F1 and then runs at F1.If
T3<54°C(129.2°F), the compressor will keep
running at the current frequency.
---T3<52°C(125.6°F), the compressor will not
limit the frequency and resume to the former
frequency.
---T3>60°C(140°F) for 5 seconds, the
compressor will stop until T3<52°C(125.6°F).
15.3.10 Evaporator low temperature T2
protection
---T2<0°C(32°F), the compressor will stop and
restart when T2
≧
5°C(41°F).
---0°C(32°F)
≦
T2<4°C(39.2°F), the compressor
frequency will be limited and decreased to the
lower level
---
4°C(39.2°F)≤T2≤7°C(44.6°F), the
compressor will keep the current frequency.
---T2>7°C(44.6°F), the compressor frequency
will not be limited.
15.4 Operation Modes and
Functions
15.4.1 Fan mode
(1) Outdoor fan and compressor stop.
(2) Temperature setting function is disabled,
and no setting temperature is displayed.
(3) Indoor fan can be set to high/med/low/auto.
(4) The louver operates same as in cooling
mode.
(5) Auto fan:
a
b
c
d
6.0°C(42.8°F)
T1-24°C(75.2°F)
e
H
(H-L)*0.75+L
(H-L)*0.5+L
(H-L)*0.25+L
L
5.0°C(41.0°F)
4.0°C(39.2°F)
2.5°C(36.5°F)
1.0°C(33.8°F)
15.4.2 Cooling Mode
15.4.2.1 Outdoor fan running rules
T4
A DC_FAN_HI_SPD_ADD
B DC_FAN_MID_SPD_ADD
C DC_FAN_MIN_SPD_ADD
D DC_FAN_SLOW_SPD_ADD
E DC_FAN_SSLOW_SPD_ADD
28
℃
(82.4°F)
19
℃
(66.2°F)
17
℃
(62.6°F)
26
℃
(78.8°F)
25
℃
(77°F)
23
℃
(73.4°F)
22
℃
(71.6°F)
20
℃
(69°F)
15.4.2.2 Indoor fan running rules
In cooling mode, indoor fan runs all the time
and the speed can be selected as high,
medium, low and auto.