Mitsubishi Electric CITY MULTI CMB-WP1016V-GA1, Service Handbook

Page: 187 / 294

[
VIII
Troubleshooting ]
- 178 -
HWE1410A GB
[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)
2) Pulse signal output and valve motion
 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.
Output (phase)
number
Output status
1 2 3 4
4 ON ON OFF OFF When valve opens (0 → C800 or H800): 4 → 3 → 2 → 1
5 OFF ON ON OFF When valve closes (C800 or H800 → 0): 1 → 2 → 3 → 4
7 OFF OFF ON ON
8 ON OFF OFF ON
4
5
6
6
5
8
4
7
GND
LED
1
2
3
12V
3
2
1
3
2
1
12V
4
6
5
8
7
1
2
3
M Microcomputer
Limit signal
(Opening
"0" signal)
Circuit board
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