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

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SV1
Discharge –
Suction Bypass
SV2
capacity
control (full
load)
SV3
capacity
control
(unload)
SV4
Discharge –
Suction Bypass
SV5b
Liquid pipes
LEV1
(SC coil)
LEV2
CH11
Crankcase
heater
CH2
CH3
Accumulator
liquid level
detection
21S4
Conductivity check
using tester.
Same as outdoor
unit LEV. However
the resistance value
is different than the
indoor unit.
Same as indoor unit
LEV.
Resistance check
Conductivity check
using tester.
AC 220 to 240 V
Open: conducting
Close: not conducting
AC 220 to 240 V
Close: conducting
Open: not conducting
AC 220 to 240 V
Open: conduction
Close: not conducting
DC 12 V stepping motor
drive valve opening amount
0 to 480 pulse (Direct drive
type)
Belt heater AC 200 to 240 V
MC ··· 200, 250: 1029
Ω
56 W
Code heater 2880
Ω
(1440
Ω
+ 1440
Ω
)
AC 220 to 240 V
20 W (10 W + 10 W)
AC 220 to 240 V
Not conducting: heating cycle
Conducting
: cooling cycle
1
Capacity control of high/low
pressure bypass when starting and
stopping.
2 Discharge pressure rise suppression.
Switching of capacity control valve inside
No. 2 compressor (Switching between
full load operation and unload operation)
(PUHN-P200·250 YMF-B only).
Raise the internal pressure of the
constant capacity accumulator.
Stop refrigerant inflow when the
constant capacity unit is stopped.
Adjusts the bypass flow rate from the
liquid piping of the outdoor unit during
cooling.
Adjusts refrigerant flow rate in the
constant capacity unit.
Refrigerant heating inside compressor.
Refrigerant heating of accumulator
liquid level detection circuit.
Switching of cooling / heating cycle.
Themist
Solenoid
Valve
Electronic
expansion
valve
Heater
4-way
valve
R
0
= 15 k
Ω
B
0/80
= 3460
R
t
=
15exp{3460( - )}
0
°
C: 15 k
Ω
10
°
C: 9.7 k
Ω
20
°
C: 6.4 k
Ω
25
°
C: 5.3 k
Ω
30
°
C: 4.3 k
Ω
40
°
C: 3.1 k
Ω
Name
Code
(Function)
Inspection method Application Product code Specification
Outdoor unit (Constant capacity unit)
TH6
(Outdoor
temperature)
TH7
TH8
TH9
(SC control)
TH10a
Heat exchanger
Gas temperature
TH10b
(Pipe
temperature)
1
Detects the outdoor air temperature.
2 Performs fan control, liquid level
control, and oil-return LEV opening
settings.
Controls LEV1 using temperature
differences among TH5, TH7, TH8,
and TH9.
Perform LEV2 control by comparing
the temperature difference with low
pressure saturation temperature.
Detect failure to open ball-valve by
checking oil balance pipe temperature.
Resistance check
1
273+t
1
273