Mitsubishi Electric CITY MULTI PUHY-400YMF-B, Service Handbook

Page: 106 / 204

–103–
(14) Control at initial starting
• When the ambient temperature is low (5
°
C or less in cooling and – 5
°
C or less in heating), initial starting will not
be performed even if the unit is started within 4 hours of the power being turned on.
• The following initial start mode will be performed when the unit is started for the first time after the power has
been turned on.
• When operation volume is low in the indoor unit, the constant
capacity unit may not run for as long as 7 hours. In order to
finish initial operation mode quickly, increase the operation
volume of the indoor unit and run under high-external tempera-
ture conditions.
<Flow chart of initial start mode>
• No.1 compressor: variable capacity unit No.1 compressor
• No.2 compressor: variable capacity unit No.2 compressor
• No.3 compressor: constant capacity unit compressor
Start of initial operation mode
End initial operation mode.
Step 1
•Only the No.1 compressor is operated (f 75 Hz)
•Operation of the No.2 and No.3 compressor is
prohibited to operate.
•Finished when cumulative operating time reaches
30 minutes.
Pause Step
• Both compressors are stopped, regardless of the
demand from the indoor units. (3 minutes)
Step 2
•
•
•
Only the No.1 compressor is operated.
Operation of the No.2 and No.3 compressor are
prohibited to operate.
Finished when the cumulative operating time
reaches 10 minutes.
Step 3
Step 4
Step 5
Step 6
•
•
•
Compressors No.1 and No.2 are both operated.
(forced)
Operation of the No.3 compressor is prohibited to
operate.
Finished when cumulative operating time reaches
5 minutes.
Compressor No.1 is operated alone, or No.1 and
No.2 compressors are both operated.
(equal to load)
Operation of the No.3 compressor is prohibited to
operate.
Finished when the length of continued operation
reaches a set amount of time.
•
•
•
•
•
•
•
•
•
If 7 hours has passed since
the power was turned on,
step 4, 5, and 6 are skipped.
At the completion of “Step 2”,
if the frequency of No.1
compressor is below the
specified value and if “Step 2”
has been completed less
than 3 times, the process
does not proceed to Step 3
but rather enters the “Pause
Step” and then repeats “Step 2”.
Compressor No.1 and No.2 are both operated.
(forced)
Operation of the No.3 compressor is prohibited to
operate.
Finished when the length of continued operation
reaches 5 minutes of time.
Compressor No.1 and No.3 are both operated.
(forced)
Operation of the No.2 compressor is prohibited to
operate.
Finished when the length of continued operation
reaches 10 minutes of time.