[ VIII Troubleshooting ]
[6] Servicing the HBC controller
3-way valve
1. Valve block
VB3 (valve block) is driven by the pulse signal from the HBC controller control board and are controlled by a stepping motor.
1) HBC controller control board and valve block (VB3)
4
Limit signal
(Opening
"0" signal)
2) Pulse signal output and valve motion
Output (phase)
number
4
5
7
8
If the LEDs (VB3a-VB3p) on the control board are lit, check the relevant valve blocks for loose connectors and faulty wiring.
Make sure that the valve blocks are properly controlling the refrigerant flow.
If the LED is unlit, check all valve blocks for proper operation.
If the problem persists after taking the above measures, replace the circuit board.
HWE1708A
5
5
6
M
6
8
6
8
7
7
3
3
2
2
1
Output status
1
2
ON
ON
OFF
ON
OFF
OFF
ON
OFF
5
4
3
2
4
1
3
2
1
1
3
4
OFF
OFF
When valve opens (0→C800 or H800): 4→3→2→1
ON
OFF
When valve closes (C800 or H800→0): 1→2→3→4
ON
ON
OFF
ON
- 200 -
Circuit board
LED
Microcomputer
GND
12V
12V
GB