Mitsubishi Electric City Multi CMB-WP108V-G, Service Manual, Page: 247 / 301

[
IX
Troubleshooting ]
- 238 - HWE1113B GB
4) Opening and closing of the valve
Water pump
2. Water pump
Check the connector and make sure that it is connected properly.
Check the driving power supply, control power supply for the pumps internal board, and check the control signal voltage by
connecting each voltage to ground. (Control signal voltage will be 0V when stopped and 6V when running at 100%)
If these are voltages are not correct then investigate the HBC pump power supply board.
If the supply voltages are correct, and the control signal is being sent and the pump will still not operate the likely causes are:
Œ
Internal pump control board failure - replace pump. (Note: The internal pump control board is usually damaged when remov-
ing and replacing the connector with the power supply turned on. Always remove the pump connector with the power supply
turned off.)
Œ
Coil failure - replace pump. If the windings have been damaged the pump will require replacing.
Œ
Internal mechanical failure such as bearing failure, turbine failure, magnet degradation. This will require pump replacement.
Before replacement the causes must be investigated and resolved. The pump shaft bearings and magnets can be easily dam-
aged by overheating due to dry running or water system blockage. Check the strainer for blockage, investigate the water
circuit for blockage and or foreign material, and that there is no air in the system or an uncontrolled leak.
-1 00 1 00 300 500 700 900 11 00 1 300 1 500
Number o f pulses
Degree
o
f
valve
opening
(water
f
low
rate)
O pening t h e valve
Closing t h e valve
6
5
4
3
2
1
Pump
Driving power
suppl y,
DC2 68 V
±
1 0%
Control power
(internal pump
board)
VDD (W h ite)
G ND (Bla ck )
VCC (Red)
V S P (Brown)
Control signal ,
0 - 6 V , 6 V = 1 00%
F G (Blue)
RPM pulse signal :
4 pulses per revolution
O uput dut y about 67%
O pen c olle c tor t y pe
5 mA c urrent
Max voltage : 50 V
DC1 5 V
±
1 0%