– 31 –
Outside air temp. (˚C)
16,0
10,3A
9,8A
10,8A
TO
15,5
11,0
10,5
Fig. 8-2-8
(4) Defrost control
1) Detection of frost
In heating operation, time duration while the
compressor operates is counted, and defrost
operation starts by any condition described
below.
a. The counted time is 28 minutes or more,
and status that temperature of the outdoor
heat exchanger detected by the outdoor
heat exchanger is –20°C or lower contin-
ued for 2 minutes or more.
b. The counted time is 28 minutes or more,
and status that temperature of the outdoor
heat exchanger detected by the outdoor
heat exchanger is –7°C or lower and
temperature lowered by 2,5 °C than the
minimum value of the outdoor heat ex-
changer during 10 to 15-minutes count
time continued for 2 minutes or more.
c. The counted time is 34 minutes or more,
and status that temperature of the outdoor
heat exchanger detected by the outdoor
heat exchanger is –5°C or lower and
temperature lowered by 3,0 °C than the
minimum value of the outdoor heat ex-
changer during 10 to 15-minutes count
time continued for 2 minutes or more.
d. If the following three conditions are satis-
fied, defrost operation (Timer defrost)
starts after heating operation for 37
minutes.
Q Setting on remote control, HEAT
(mode), HIGH (Fan), 30°C (temp.).
R Room temp. is 19°C to 24°C, and
outside air temp. is 5°C or lower.
S Defrost operation has been already
performed once.
2) Defrost operation
Operation of the compressor is stopped
once, turn off power coupler for four-way
valve after 10 seconds, and then exchange
the four-way valve.
After 20 seconds, restart operation of the
compressor. Turn off the outdoor fan just
when the compressor stopped.
If temperature of the indoor heat exchanger
lowered than 38°C, stop the indoor fan.
3) Defrost reset
Resetting operation from defrost to heating is
performed when any one of the following
conditions is satisfied.
a. Temperature of the outdoor heat ex-
changer rose to +8°C or higher.
b. A status that temperature of the outdoor
heat exchanger is +5°C or higher contin-
ued for 80 seconds.
c. Defrost operation continued for 10 min-
utes.
In resetting defrost operation, the compressor
stops for 50 seconds if defrost has started
under condition a. to c. in item 1), but the
compressor is reset to heating operation
keeping operated if defrost has started under
condition d. in item 1).
(5) Louver control
The vertical air flow louvers are automatically set
to heating position or heat memory position.
When the compressor is turned off by high-temp.
release control, the vertical air flow louvers close
once and then return to the position of previous
time.