Mitsubishi Electric CITY MULTI PUHY-400YMF-C, Руководство по обслуживанию

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Switching No. 3 compressor from operation to stopping
When the required performance is exceeded with the No. 1 and No. 2 variable capacity unit compressors and
constant capacity unit No. 3 compressor in operation, the No. 3 compressor will be stopped.
3) Pressure control
• The upper limit value for the high pressure (Pd) has been set for each frequency. When this value is exceeded,
frequency is reduced every 30 seconds.
• While the constant capacity unit is in operation, if the high pressure (63HS) value exceeds
the constant capacity unit compressor will be stopped.
2.55 MPa,
4) Discharge temperature control
The discharge temperature of the compressor (Variable capacity unit: TH11, TH12, Constant capacity unit:
TH11) is monitored during the operation. If the upper limit is exceeded, the frequency is reduced by 5 Hz.
• Control is performed every 30 seconds after 30 seconds at the compressor starting.
• The operating temperature is 124˚C (No.1 compressor) or 115˚C (No. 2, 3 compressor).
While the constant capacity unit is in operation, if the constant capacity unit discharge temperature (TH11)
exceeds 115˚C, the constant capacity unit compressor will be stopped.
5) Compressor frequency control
Ordinary control
The ordinary control is performed after the following times have passed.
• 30 seconds after the start of the compressor or 30 seconds after the completion of defrosting.
• 30 seconds after frequency control operation by the discharge temperature or the high pressure.
Amount of frequency fluctuation
The amount of frequency fluctuation is controlled in response to the evaporation temperature (Te) and the
condensation temperature (Tc) so that it will approached the target values.
Frequency control back-up by the bypass valve
Frequency control is backed-up b
compressor is operated at its lowest frequency
.
• Cooling
After the compressor has been operated for 15 minutes and only the No. 1 compressor is operated in un-load
(its lowest frequency), the bypass valve is turned ON when the low pressure (63LS) is
or less and
turned OFF when it is 0.196 MPa or more.
0.098 MPa
• Heating
After the compressor has been operated for 3 minutes and only the No. 1 compressor is operated in un-load
alve is turned ON when the high pressure (Pd) exceeds
and turned OFF when it is 2.35 MPa or less.
ON
OFF
0.098 MPa 0.196 MPa
ON
OFF
2.35 MPa 2.65 MPa
the
the
lowest frequency), the by passypass vlve (its
2.65 MPa
2
1
1
2
2
3
y turning on (opening) the bypass valve (SV4) when only the No. 1