Mitsubishi Electric CMB-WM108V-AA Service Handbook page 117

[ VI Control ]
Water rate valve control
-3- Valve block (VB3) water flow rate adjustment
Depending on the capacity required, periodic control is performed every one minute to keep the temperature difference be-
tween the heat exchanger outlet pipe temperature and indoor unit port pipe temperature within 4.0ºC for cooling and 4.5ºC for
heating, and the opening is controlled in the range between 85 and 700 (cooling) or 900 and 1600 (Heating) pulses.
For the degree of valve opening, C800 or H800 indicate fully open and 0 indicates fully closed.
3-way valve control
-4- Valve block (VB3) water flow path switching control
The following table shows the control pattern of the 3-way valve in different operation modes to switch the water flow.
(1) Cooling-only Thermo-ON, Cooling-only Thermo-OFF, Cooling-only test run, Heating-only Thermo ON, and Heating-
only Thermo OFF
Outdoor unit operation mode
Cooling-only Thermo-ON
Heating-only Thermo ON
Cooling-only Thermo-OFF
Heating-only Thermo OFF
Cooling-only test run
(2) Heating-main Thermo-ON, Heating-main Thermo-OFF, Cooling-main Thermo-ON, and Cooling-main Thermo-OFF
Outdoor unit operation mode
Heating-main Thermo-ON
Cooling-main Thermo-ON
Heating-main Thermo-OFF
Cooling-main Thermo-OFF
<Designated degree of valve opening>
- 1: 800 pulse
- 2: 85~700 pulses
- 3: 900~1600 pulses
HWE1708A
Connected indoor unit VB3 command value
operation mode
Stop
Fan
Thermo-ON
Thermo-OFF
Stop
Fan
Thermo-OFF
Stop
Fan
Thermo-ON
Thermo-OFF
Connected indoor unit VB3 command value
operation mode
Stop
Fan
Cooling Thermo-ON
Cooling Thermo-OFF
Heating Thermo-ON
Heating Thermo-OFF
Stop
Fan
Cooling Thermo-OFF
Heating Thermo-OFF
- 108 -
for opening
1
1
2 or 3
1
1
1
1
1
1
2 or 3
1
for opening
1
1
2
1
3
1
1
1
1
1
GB