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
3H
2M
1L
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.
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