Carrier 38MPRA Series Service Manual page 17

HEATING Mode
Compressor Control
1. Reach the configured temperature:
• If the following conditions are satisfied, the compressor stops:
• While the calculated frequency (fb) is less than the minimum
limit frequency (FminC).
• When the protective time is more than or equal to ten minutes.
• When T1 is higher than or equal to Tsc+HDIFTEMP2.
NOTE: HDIFTEMP2 is the EEPROM setting parameter.
° °
It is 4 F (2 C).
• If one of the following conditions is satisfied, regardless of
time:
• Compressor running frequency is more than test frequency.
• When the compressor running frequency is equal to the test
frequency, T4 is more than 59°F (15°C) or no T4 or T4 fault.
• A change in the setting temperature.
• TURBO or SLEEP function ON or OFF.
2. When the current is higher than the predefined safe value, the surge
protection is activated, causing the compressor to cease operations.
Indoor Fan Control
1. In the HEATING mode, the indoor fan operates continuously. The
fan speed can be set to 1%-100%, or muted.
2. AUTO fan
• Rise curve
• When T1-Tsc is higher than -3°F (-1.5°C), fan speed reduces
to 80%;
• When T1-Tsc is higher than 0°F (0°C), fan speed reduces to
60%;
• When T1-Tsc is higher than 1°F (0.5°C), fan speed reduces to
40%;
• When T1-Tsc is higher than 2°F (1°C), fan speed reduces to
20%.
•Descent curve
•When T1-Tsc is lower than or equal to 1°F (0.5°C), fan speed
increases to 20%;
• When T1-Tsc is lower than or equal to 0°F (0°C), fan speed
increases to 60%;
• When T1-Tsc is lower than or equal to -3°F (-1.5°C), fan
speed increases to 80%;
• When T1-Tsc is lower than or equal to -1.5°F (-3°C), fan
speed increases to 100%.
Outdoor Fan Control
•The outdoor unit runs at a different fan speed according to T4
and the compressor running frequency.
• For different outdoor units, the fan speeds differ.
SG-38MPRA-02
DEFROSTING Mode
• The unit enters the DEFROSTING mode according to changes in
the temperature value of T3, T4 as well as the compressor running
time.
• In the DEFROSTING mode, the compressor continues to run, the
indoor and outdoor motor will cease operation, the indoor unit's
defrost light turn on, and the
• If any one of the following conditions is satisfied, defrosting ends
and the machine switches to the normal HEATING mode:
• T3 rises above TCDE1C.
• T3 maintained above TCDE2C for 80 seconds.
• Unit runs for 15 minutes consecutively in the DEFROSTING
mode.
Evaporator Temperature Protection
• Off: Compressor stops.
• Decrease: Decrease the running frequency to the lower level per
20 seconds.
• Hold: Keep the current frequency.
• Resume: No limitation for frequency.
AUTO Mode
• This mode can be selected with the remote controller and the
setting temperature can be changed between 61°F~86°F
(16°C~30°C).
• In the AUTO mode, the unit selects the COOLING, HEATING,
AUTO-DRYING or FAN-ONLY mode on the basis of T1,Ts, T4
and relative humidity.
• If the setting temperature is modified, the unit selects a new
running function.
DRY Mode
In the DRY mode, the air conditioner operates the same as auto fan in
the COOLING mode.
1. Mute function is active.
• All protections are activated and operate the same as they do
that in COOLING mode.
2. Low Room Temperature Protection
• If the room temperature is lower than 10°C, the compressor
ceases operations and does not resume until the room
temperature exceeds 12°C.
Specifications subject to change without notice.
symbol appears.
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