II - 6
Processes and Functions
SM830052
2
3. Reverse Cycle Starting Control
At the start of heating operation, the cooling cycle operates for 50 seconds. During this time, the outdoor and indoor
fans are stopped.
Reverse-Cycle start conditions:
(1)
When starting heating operation after 60 minutes of stop operation
(2)
When starting heating operation for the first time after switching on the power
(3)
Reverse-cycle start control details
After 50 seconds of reverse-cycle (cooling) operation, the outdoor unit stops for 20 seconds, then starts normal
operation.
50 seconds
20 seconds
P/C compressor
OFF
Compressor capacity control
OFF
AC compressor
OFF
↑
OFF
4-way valve
?
OFF
OFF
On after start
Outdoor fan
STOP
STOP
H
Low-pressure valve
ON
Compressor capacity control
ON
High-pressure valve
OFF
↑
OFF
Save valve
ON
Save valve control
ON
16
H (M)
11
M (L)
L (STOP)
21
H (M · L · STOP)
16
H (M · L)
H (M)
4. Outdoor Fan Control
(1)
Outdoor fan mode
Mode
Fan
3
H
2
M
1
L
0
STOP
(2)
Initial control
For the first 30 seconds after operation start, outdoor fans are controlled according to the outdoor temperature as
shown below.
When the fans are started, they rotate at high speed for 12 seconds.
Cooling
Heating
Outdoor temperature
Outdoor temperature
* The outdoor fans rotate at the mode in the parentheses ( ) according to the operating capacity.
(3)
The fan mode is then switched up or down according to the operating conditions.
(4)
In order to detect the outdoor temperature, the fans rotate at high speed under the conditions below.
¶
12 seconds immediately before compressor starts.
¶
For 1 minute after compressor stopps due to thermo-cycle
5. 4-way Valve Switching Control
(1)
In normal operation, the 4-way valve is off for cooling and on for heating.
(2)
When the outdoor unit is stopped, the previous mode is maintained.
6. Save Valve Control
(1)
The save valve is switched on according to the tables shown in Section 1. “Compressor Control.”
(2)
The save valve is on when the outdoor unit is stopped.
