Mitsubishi Electric HP120TNU-A Service Handbook page 272

[8-9 Troubleshooting Problems with Major Components on BC Controller ]
1) BC controller: Phenomena when the pressure sensor is connected wrongly (reverse connection of P1 and P3) to the board.
Cooling-only
Normal Non-cooling
2) Check the self-diagnosis switch (Outdoor control board SW4 and SW6).
Measurement
Symbol SW4 setting value
data
Outdoor ON
high
63HS1
pressure
1 2 3 4 5
ON
Outdoor low
63LS
pressure
1 2 3 4 5
ON
BC controller
pressure PS1
(liquid side)
2 3 4 5
1
BC controller
ON
pressure
PS3
(intermediate
part)
1 2 3 4 5
Sub BC
ON
controller
pressure
PS3
(intermediate
1 2 3 4 5
part) (Sub 1)
Sub BC
controller ON
pressure
PS3
(intermediate
1 2 3 4 5
part) (Sub 2)
Sub BC
controller ON
pressure
PS3
(intermediate
1 2 3 4 5
part) (Sub 3)
Sub BC
controller ON
pressure
PS3
(intermediate
2 3 4 5
1
part) (Sub 4)
ON
1 2 3 4 5 6 7 8 9 10
3) Check whether CNP1 (liquid side) connector on the BC controller control board and the connector CNP2 (intermediate part)
are not disconnected or not loose.
4) Check the pressure value on the self-diagnosis switch (same as note 2) with the connector of the applied pressure sensor is
disconnected from the board.
HWE18220_GB
Cooling-main
Indoor heating SC small
SC11 large
Heating indoor Thermo ON
SC16 small
Especially noise is large.
PHM large
SW6 setting value
ON
6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
ON
6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
ON
6 7 8 9 10 2 3 4 5 6 7 8 9 10
1
ON
6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
ON
6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
ON
6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
ON
6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
ON
6 7 8 9 10 2 3 4 5 6 7 8 9 10
1
The figure at left shows that the switches 1 through 5 are set to ON and 6 through 10 are set to OFF.
Symptoms
Heating only
SC11 large
SC16 small
PHM large
Measurement
Symbol SW4 setting value
data
Sub BC
ON
controller
pressure PS3
(intermediate
2 3 4
1
part) (Sub 5)
Sub BC
ON
controller
pressure
PS3
(intermediate
2 3 4
1
part) (Sub 6)
Sub BC
ON
controller
pressure
PS3
(intermediate
2 3 4
1
part) (Sub 7)
Sub BC
ON
controller
pressure PS3
(intermediate
1 2 3 4
part) (Sub 8)
Sub BC
ON
controller
pressure
PS3
(intermediate
1 2 3 4
part) (Sub 9)
Sub BC
ON
controller
pressure
PS3
(intermediate
2 3 4
1
part) (Sub 10)
Sub BC
ON
controller
pressure PS3
(intermediate
1 2 3 4
part) (Sub 11)
Heating main
Non-cooling
SC11 large
Indoor heating SC small
SC16 small
Heating indoor Thermo ON
PHM large
Especially noise is large.
SW6 setting value
ON
5 6 7 8 9 10 2 3 4 5 6 7 8
1
ON
5 6 7 8 9 10 2 3 4 5 6 7 8
1
ON
5 6 7 8 9 10 2 3 4 5 6 7 8
1
ON
5 6 7 8 9 10 1 2 3 4 5 6 7 8
ON
5 6 7 8 9 10 1 2 3 4 5 6 7 8
ON
5 6 7 8 9 10 2 3 4 5 6 7 8
1
ON
5 6 7 8 9 10 1 2 3 4 5 6 7 8
chapter 8 -
9 10
9 10
9 10
9 10
9 10
9 10
9 10
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