Mitsubishi Electric CITY MULTI PUHY-P400YEM-A Service Handbook page 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
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".
If 7 hours has passed since
the power was turned on,
step 4, 5, and 6 are skipped.
-100-
Start of initial operation mode
Step 1
•All the No.1 compressor is operated (f
•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 is
prohibited.
• Finished when the cumulative operating time
reaches 10 minutes.
Step 3
• Compressors No.1 and No.2 are both operated.
(forced)
• Operation of the No.3 compressor is prohibited.
• Finished when cumulative operating time reaches
5 minutes.
Step 4
•
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.
•
Finished when the length of continued operation
reaches a set amount of time.
Step 5
•
Compressor No.1 and No.2 are both operated.
(forced)
•
Operation of the No.3 compressor is prohibited.
•
Finished when the length of continued operation
reaches 5 minutes of time.
Step 6
•
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.
End initial operation mode.
75 Hz)