Mitsubishi Electric City Multi CMB-WP108V-G, Service Manual, Page: 37 / 301

[
II
Restrictions ]
- 28 - HWE1113B GB
3. Demand control
1) General outline of control
Demand control is performed by using the external signal input to the 1-2 and 1-3 pins of CN3D on the outdoor units (OC and OS).
Between 2 and 8 steps of demand control is possible by setting Dip SW4-4 on the outdoor units (OC and OS).
*1 Available demand functions
Single-outdoor-unit system: 2 and 4 steps shown in the rows 1 and 2 in the table above only.
Two-outdoor-unit system OC+OS : 2-8 steps shown in the rows 1, 2, 3, and 4 in the table above only.
*2 External signal is input to CN3D on the outdoor unit whose SW4-4 is set to ON. When SW4-4 is set to OFF on all outdoor units,
the signal is input to the CN3D on the OC.
Outdoor units whose SW4-4 is set to ON are selectable in a single refrigerant system.
*3 If wrong sequence of steps are taken, the units may go into the Thermo-OFF (compressor stop) mode.
Ex) When switching from 100% to 50%
(Incorrect) 100%
ĺ
0%
ĺ
50% The units may go into the Thermo-OFF mode.
(Correct) 100%
ĺ
75%
ĺ
50%
*4 The percentage of the demand listed in the table above is an approximate value based on the compressor volume and does
not necessarily correspond with the actual capacity.
*5 Notes on using demand control in combination with the low-noise mode
To enable the low-noise mode, it is necessary to short-circuit 1-2 pin of CN3D on the outdoor unit whose SW4-4 is set to OFF.
When SW4-4 is set to ON on all outdoor units, the following operations cannot be performed.
Œ
Performing 4-step demand in combination with the low-noise operation in a single-outdoor-unit system.
Œ
Performing 8-step demand in combination with the low-noise operation in a two-outdoor-unit system.
2) Contact input and control content
2-step demand control
The same control as the Thermo-OFF is performed by closing 1-3 pin of CN3D.
4-step demand control (When SW4-4 is set to ON on an outdoor unit)
Demand capacity is shown below.
8-step demand control (When SW4-4 is set to ON on two outdoor units)
Demand capacity is shown below.
*1. The outdoor units whose SW4-4 is set to ON are designated as No. 1 and No. 2 in the order of address from small to large.
Ex) When outdoor units whose SW4-4 is set to ON are designated as OC and OS, OC=No. 1 and OS=No. 2.
No Demand control switch
DipSW4-4
Input to CN3D*
2
OC OS
1 2 steps (0-100%) OFF OFF OC
2
4 steps (0-50-75-100%)
ON OFF OC
3 OFF ON OS
4
8 steps
(0-25-38-50-63-75-88-100%)
ON ON OC and OS
CN3D
1-3
Open 100%
Close 0%
CN3D 1-2P
1-3P Open Close
Open 100% 75%
Close 0% 50%
8-step demand No.2 CN3D
1-2P Open Short-circuit
No.1 CN3D 1-2P 1-3P Open Short-circuit Open Short-circuit
Open Open 100% 50% 88% 75%
Short-circuit 50% 0% 38% 25%
Short-circuit Open 88% 38% 75% 63%
Short-circuit 75% 25% 63% 50%