Mitsubishi Electric CITY MULTI CMB-WP1016V-GA1 Installation Manual Download Page 12

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Note:
*1. Connection of multiple indoor units with one connection (or joint pipe)

•

Total capacity of connectable indoor units: Less than 80

•

Number of connectable indoor units: Maximum 3 Sets

•

Selection of water piping
Select the size according to the total capacity of indoor units to be installed down-
stream.

•

Please group units that operate on 1 branch.

•

When multiple indoor units are connected to a single port, install a pressure con-
trol valve in the pipe to equalize the pressure of all indoor units.

11. Please refer to the [Fig. 5.2.3] when connecting the water supply.

[Fig. 5.2.3] (P.5)

12. Use formula 0.1 [MPa] < 0.01 + 0.01 x A < 0.16 [MPa] for the supply pressure

range to be used.
(A: Head pressure (m) between the HBC and the highest indoor unit)
If the supply pressure is greater than 0.16 MPa, use a pressure reducing valve to
keep the pressure within the range.
If the head pressure is unknown, set it to 0.16 MPa.

13. Before performing a pressure test on the pipes in the water circuit, be sure to

install a shutoff valve on the inlet/outlet water pipes of the indoor units. Also,
install a strainer on the field-installed water pipes for easy operation and mainte-
nance.

14. Apply insulation to the indoor unit pipework, strainer, shutoff valve, and pressure

reducing valve.

15. Please do not use a corrosion inhibitor in the water system.
16.

When installing the HBC unit in an environment which may drop below 0°C,
please add antifreeze solution (Propylene Glycol only) to the circulating
water according to the local regulations.

5.3. Water treatment and quality control

To preserve water quality, use the closed type of water circuit. When the circulating
water quality is poor, the water heat exchanger can develop scale, leading to a
reduction in heat-exchange power and possible corrosion. Pay careful attention to
water processing and water quality control when installing the water circulation sys-
tem.
•

Removing of foreign objects or impurities within the pipes.
During installation, make sure that foreign objects, such as welding fragments,
sealant particles, or rust, do not enter the pipes.

•

Water Quality Processing

Water quality standard

6. Electrical work



Consult all related regulations and power companies beforehand.

Warning:

Electrical work should be handled by qualified electrical engineers in accord-
ance with all related regulations and attached instruction manuals. Special cir-
cuits should also be used. If there is a lack of power capacity or a deficiency in
electrical work, it may cause a risk of electric shock or fire.



Connect all wires securely.

•

Fix power source wiring to control box by using buffer bushing for tensile force
(PG connection or the like).

[Fig. 6.0.1] (P.5)



Never connect the power cable to the terminal board for control cables.
(Otherwise it may be broken.)



Be sure to wire between the control wire terminal boards for indoor unit,
outdoor unit and HBC/Sub-HBC controller.

Use non-polarized 2-wire as transmission cables.
Use 2-core shielding cables (CVVS, CPEVS) of more than 1.25 mm

in diameter as

transmission cables.

The switch capacity of the main power to HBC/Sub-HBC controllers and the wire size
are as follows:

•

For other detailed information, refer to the outdoor unit installation manual.

•

Power supply cords of appliances shall not be lighter than design 245 IEC 53 or
227 IEC 53.

•

A switch with at least 3 mm contact separation in each pole shall be provided by
the Air conditioner installation.

Caution:

Do not use anything other than the correct capacity fuse and breaker. Using
fuse, conductor or copper wire with too large capacity may cause a risk of mal-
function or fire.
Ensure that the outdoor units are put to the ground. Do not connect the earth
cable to any gas pipe, water pipe, lightening rod or telephone earth cable. In-
complete grounding may cause a risk of electric shock.

7. Setting addresses and operating units

The address switch of each HBC/Sub-HBC controller is set to “000” when shipped
from the factory.
•

Set the address switch to an address that equals the lowest address of the indoor
units that are connected to the HBC/Sub-HBC controller plus 50.



Assign the HBC controller address that equals the lowest address of the
indoor units that are connected to the HBC/Sub-HBC controller plus 50.
However, if the address overlaps any other units’ addresses, assign the
address that equals the next lowest address plus 50.

•

Please refer to the outdoor unit installation manual.

Up to three units for 1 branch hole; total capacity: below 80 (but in same mode, cool-
ing/heating)

Shutoff valve (field supply)

Pressure control valve (field supply)

Auto air vent valve (Highest point on the water pipe) (field supply)

Water pipework is screw connections

HBC controller

Water pipe

Pressure gauge (field supply)

Check valve (field supply)

Shutoff valve (field supply)

Pressure reducing valve (field supply)

Strainer (field supply)

Depending on the quality of the cold-temperature water used in the aircondi-
tioner, the copper piping of the heat exchanger may corrode.
Regular water quality processing is recommended.
If a water supply tank is installed, keep air contact to a minimum, and keep
the level of dissolved oxygen in the water no higher than 1mg/

ℓ

Items

Low to mid-range

temperature water system

Tendency

Recirculating

water

[20<T<60°C]

[68<T<140°F]

Make-up

water

Corrosive