Mitsubishi Electric ecodan EHPT17X-VM2D, Service Manual

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69
OCH714D
Part Name Checkpoints
Earth leakage circuit breaker for heater If a short circuit occurs on the booster heater, immersion heater, or each
power line, a short-circuit breaker will trip and power source will be blocked.
Eliminate the causes of short circuit and then turn on the breaker again.
Relay for heater
R S T A1 A2
U V W
When the applied voltage is not 230 VAC across the terminals A1-A2, check
the terminals R-U, S-V, and T-W are open.
When the applied voltage is 230 VAC across the terminals A1-A2, check the
terminals R-U, S-V, and T-W are short.
3-way valve (Stepping motor) Measure the resistance between the terminals with a multimeter.
(Winding temperature 20°C)
Normal Abnormal
Purple-Yellow Purple-Blue Purple Gray Purple-Pink
Open or Short
35 Ω
3-way valve (AC motor)
Measure the resistance between the terminals with a multimeter.
(Winding temperature 20°C)
Terminal Normal Abnormal
Blue-Black
or Blue-Brown*
11 Ω Open or Short
*One will be 11Ω and the other will be open.
Pressure sensor
Mixing valve (1) Check if wirings are correct.
TBO.2-1: Black
TBO.2-2: Blue
TBO.2-3: Brown
(2) Remove the motor part from the mixing valve and check if it functions prop -
erly as follows:
• The motor dial rotates in a CW direction when 230 V is applied between
brown and blue.
• The motor dial rotates in a CCW direction when 230 V is applied between
black and blue.
(3) If the motor functions properly, the valve may be locked by some cause:
Remove the valve to check for clogging inside.
Thermistors Disconnect the connector then measure the resistance with a multimeter.
(At ambient temperatures of 10 to 30°C.)
Thermistor Normal Abnormal
TH1
4.3 - 9.5 kΩ Open or short
TH2
THW1
THW2
THW5A
THW5B
THW6
THW7
THW8
THW9
THW10
40 - 100 kΩ Open or short
THWB1
M
Blue
Purple
Pink
Gray Yellow
M
Black
Blue
Brown
1
3
4
RD
BK
WH
SENSOR
5 VDC
Vout
MICRO
PROCESSOR
FTC CONTROLLER BOARD
1
-
3
: 5 V (DC)
4
-
3
: Output Vout (DC)
CN401 WH
0.5
2.5 5
2.5
4.5
Vout (V)
PRESSURE
(MPa)
1
3
4
RD
BK
WH
SENSOR
5 VDC
Vout
MICRO
PROCESSOR
FTC CONTROLLER BOARD
1
-
3
: 5 V (DC)
4
-
3
: Output Vout (DC)
CN401 WH
0.5
2.5 5
2.5
4.5
Vout (V)
PRESSURE
(MPa)
CCW (Open)
Black
CW (Close)
Brown
N
Blue
M
1~