Mitsubishi Electric EHST20C-VM2C.UK Service Manual page 19

Option 2: Cylinder unit powered by independent source.
If the cylinder unit and outdoor unit have separate power supplies, the following
requirements MUST be carried out:
• Change the interconnected wiring in the control and electrical box of the
cylinder unit (see Figure 7-3).
• Turn the outdoor unit DIP switch SW8-3 to ON.
• Turn on the outdoor unit BEFORE the cylinder unit.
• Power by independent source is not available for particular models of
outdoor unit model. For more detail, refer to the connecting outdoor unit
Installation Manual.
<1 phase>
Affix label B that is included with the manuals near
each wiring diagram for cylinder unit and outdoor units.
Power
supply
~/N
Earth
230 V
leakage
50 Hz
circuit
breaker
*1
Description
Booster heater (Primary circuit)
Immersion heater (DHW tank)
Cylinder unit power supply
Cylinder unit input capacity
Main switch (Breaker)
Cylinder unit power supply
Cylinder unit power supply earth
Cylinder unit - Outdoor unit
Cylinder unit - Outdoor unit earth
Cylinder unit L - N
Cylinder unit - Outdoor unit S1 - S2
Cylinder unit - Outdoor unit S2 - S3
*1. A breaker with at least 3.0 mm contact separation in each pole shall be provided. Use earth leakage breaker (NV).
The breaker shall be provided to ensure disconnection of all active phase conductors of the supply.
*2. Max. 120 m
*3. The values given in the table above are not always measured against the ground value.
Note: 1. Wiring size must comply with the applicable local and national codes.
2. Indoor unit/outdoor unit connecting cords shall not be lighter than polychloroprene sheathed flexible cord. (Design 60245 IEC 57)
Indoor unit power supply cords shall not be lighter than polychloroprene sheathed flexible cord. (Design 60227 IEC 53)
3. Install an earth longer than other cables.
4. Please keep enough output capacity of power supply for each heater. Insufficient power supply capacity might cause chattering.
OCH570
Power
Earth
supply
leakage
~/N
circuit
230 V
breaker
50 Hz
*1
Outdoor unit
Wiring L
circuit
breaker N
or
Isolating
switch
Power
supply
~/N
230 V
50 Hz
Power
supply
~/N
230 V
50 Hz
<Figure 7-4>
Electrical connections 1 phase
Power supply Capacity
~/N 230 V 50 Hz 2 kW
6 kW
~/N 230 V 50 Hz 3 kW
~/N 230 V 50 Hz
*1
2 × Min. 1.5
1 × Min. 1.5
*2 2 × Min. 0.3
*3 230 V AC
*3
*3
Initial settings
(Power supplied by
outdoor unit)
Modified settings
(Separate power
supply to the cylinder
unit)
Cylinder unit
TB1
Wiring
L To control
circuit
board
breaker
N
or
Isolating
switch
S1
S1
S2 S2
S3
S3
ECB1
For
Wiring
L
booster
circuit
heater
breaker
N
(Primary circuit)
or
Isolating
switch
ECB2
For
Immersion
Wiring L
heater
circuit
(DHW tank)
breaker
N
or
Isolating
switch
Breaker Wiring
16 A *1 2.5 mm²
32 A *1 6.0 mm²
16 A *1 2.5 mm²
16 A
—
—
24 V DC
19
L
N
White
CN01
Cylinder unit
S1
control board
S2
S3
L
N
White
CN01
Cylinder unit
S1
control board
S2
S3
<Figure 7-3>
*1 If the installed earth leakage circuit breaker
does not have an over-current protection
function, install a breaker with that function
along the same power line.