COMFORT-AIRE Century VMH-SV Series Service Manual page 31

2) Auto fan
For DC fan motor units:
• Rise curve
• When T1-Tsc is higher than -1.5°C, fan speed
reduces to 80%;
• When T1-Tsc is higher than 0°C, fan speed reduces
to 60%;
• When T1-Tsc is higher than 0.5°C, fan speed
reduces to 40%;
• When T1-Tsc is higher than 1°C, fan speed reduces
to 20%.
• Descent curve
• When T1-Tsc is lower than or equal to 0.5°C, fan
speed increases to 40%;
• When T1-Tsc is lower than or equal to 0°C, fan
speed increases to 60%;
• When T1-Tsc is lower than or equal to -1.5°C, fan
speed increases to 80%;
• When T1-Tsc is lower than or equal to -3°C, fan
speed increases to 100%.
For AC fan motor units:
3.4.3 Outdoor Fan Control:
• The outdoor unit will be run at different fan speed
according to T4 and compressor running frequency.
• For different outdoor units, the fan speeds are
different.
3.4.4 Defrosting mode
• The unit enters defrosting mode according to changes
in the temperature value of T3, T4 as well as the
compressor running time.
• In defrosting mode, the compressor continues to run,
the indoor and outdoor motor will cease operation,
the defrost light of the indoor unit will turn on, and
the " " symbol is displayed.
• If any one of the following conditions is satisfied,
defrosting ends and the machine switches to normal
heating mode:
• T3 rises above TCDE1°C.
• T3 maintained above TCDE2°C for 80 seconds.
• Unit runs for 15 minutes consecutively in defrosting
• If T4 is lower than or equal to -22°C and compressor
running time is more than TIMING_DEFROST_TIME,
if any one of the following conditions is satisfied,
defrosting ends and the machine switches to normal
heating mode:
• Unit runs for 10 minutes consecutively in defrosting
• T3 rises above
For some models:
• If T3 is lower than 3°C and compressor running time
is more than 120 minutes, at this time, if T3 is lower
than TCDI1+4°C(39.2°F) for 3 minutes, the unit enters
defrosting mode.
For some models:
• If any one of the following conditions is satisfied, the
unit enters defrosting mode
• If T3 or T4 is lower than -3°C for 30 seconds,Ts-T1
• If T3 or T4 is lower than -3°C for 30 seconds and
• If any one of the following conditions is satisfied,
defrosting ends and the machine switches to normal
heating mode:
• T3 rises above TCDE1+4°C.
• T3 maintained above TCDE2+4°C for 80 seconds.
• Unit runs for 15 minutes consecutively in defrosting
3.4.5
• Off: Compressor stops.
 Product Features
Product Features 6
mode.
mode.
10°C.
is lower than 5°C and compressor running time is
more than EE_TIME_DEFROST7.
compressor running time is more than EE_TIME_
DEFROST7+30.
mode.
Evaporator Temperature Protection
6 