Defrost Mode - Heat Controller B-DVH09SD-0 Service Manual

Heat Controller
9.3.2 Outdoor Fan Operation-Heating Mode
The outdoor fan operates based on the Outdoor
Ambient Temperature (T4):
T4
°F (°C)
17
63 (17)
15
59 (15)
When the outdoor ambient temperature T4 is
above 63°F(17°C), the outdoor fan runs low
speed, however when the temperature is below
this, the fan speed increases to high and
continues to run at high speed when the
temperature is 63°F(17°C) or below.
9.3.3 Indoor Fan Operation-Heating Mode
The indoor fan runs based on the evaporator
coil temperature (T2) as follows:
T2°
T2
TEL8
TEL7
TEL6
TEL5
TEL4
TEL3
TEL2
TEL1
TEL0
TEL0 TEL1 TEL2
75°F 83°F
(24°C) (28°C)
Notes:
• If the compressor stops due to the room
temperature rising, the indoor fan will be
Low
High
Setting
Medium
Low
Breeze
Super
Breeze
Off
TEL3 TEL4 TEL5 TEL6 TEL7
90°F 95°F 97°F 102°F
(32°C) (35°C) (36°C) (39°C)
forced to run for 127seconds in breeze
mode.
anti-cold-wind is disabled.
If the unit runs in forced operation mode,
•
the indoor fan will run with rating speed
and the
disabled.
9.3.3.1 Auto Fan Operation-Heating Mode
When the fan is placed in auto mode, while the
unit is in cooling mode, the auto fan operation
takes into account the difference (ΔT) in indoor
room temperature (T1) and the set point
temperature (Ts):
ΔT =T1-Ts
ΔT°
2.5
2
1.5
1
The indoor fan will run at low speed when the
ΔT is greater than 2.5Degrees, medium speed
when the ΔT is between 2.5 and 1.5 degrees,
and high speed between 1.5 and 1 degrees or
less.

9.4 Defrost Mode

9.4.1 Defrosting Conditions:
When T4>32°F(0°C), if the following two items
are satisfied, the units start defrosting:
1. T3<38°F(3°C) for 40 minutes and T3
remains lower than 21°F(-6°C) for more
than 3 minutes.
2. T3<38°F(3°C) for 80 minutes and T3
remains lower than 25°F(-4°C) for more
TEL8
than 3 minutes.
When T4<32°F(0°C), both the first and second
111°F
conditions are satisfied, then the program will
(44°C)
determine if T2 has decreased more than
41°F(5°C) or not. When T2 has decreased
more than 41°F(5°C), the unit enter the defrost
mode.
21
23
DVC/DVH Inverter Mini-Split
During this period,
anti-cold-wind function
Low
Medium
High
the
is