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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
system.
•
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
1 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.
6. Electrical work
Consult all related regulations and power companies beforehand.
Warning:
Electrical work should be handled by qualified electrical engineers in
accordance with all related regulations and attached instruction manuals.
Special circuits 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.7)
CMH-WM250V-A
CMH-WM350V-A
CMH-WM500V-A
A Control box
C ø32 hole (closed rubber bushing)
E Clip cables here
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 hydro unit.
Use non-polarized 2-wire as transmission cables.
Use 2-core shielding cables (CVVS, CPEVS) of more than 1.25 mm
transmission cables.
7. Setting addresses and operating units
The address switch of each hydro unit is set to "000" when shipped from the factory.
•
Set the address switch to an address that equals the address of the outdoor units
that are connected to the hydro unit plus 1.
•
Please refer to the outdoor unit installation manual.
8. Test run
Before commencing a test run please check the
following:
After installing, piping and wiring the indoor units and hydro units, check
to see again that there is no refrigerant leakage, water leakage, the indoor
unit inlet and outlet piped backwards, and no slack on power and control
cables.
Use a 500 V tester to check that there is an insulation resistance of more
than 1.0 MΩ between the power terminal block and the ground. If it is less
than 1.0 MΩ, do not operate the unit.
•
When water has been supplied to the water pipework, purge the system of air.
The details of air purging can be found separately in the water circuit
maintenance manual.
B Power source wiring
D Transmission wiring
in diameter as
2
2 Water quality standard
Items
pH (25°C) [77°F]
Electric conductivity
(mS/m) (25°C) [77°F]
(µ s/cm) (25°C) [77°F]
Chloride ion
Sulfate ion
(mg SO4
Acid consumption (pH4.8)
(mg CaCO
Total hardness
(mg CaCO
Calcium hardness
(mg CaCO
Ionic silica
(mg SiO
Iron
Copper
Sulfide ion
Ammonium ion
(mg NH
Residual chlorine
Free carbon dioxide
(mg CO
Ryzner stability index
Reference: Guideline of Water Quality for Refrigeration and Air Conditioning
Equipment. (JRA GL02E-1994)
3 Consult with a specialist about water quality control methods and calculations
before using anti-corrosive solutions.
The switch capacity of the main power to hydro unit and the wire size are as follows:
Switch (A)
Molded case
circuit breaker
Capacity
Fuse
16
16
20 A
•
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.
•
When air flow decrease is detected of a circulation fan beside the hydro unit
installed at the height of less than 1.8 m from the ground, the system must be
powered off within 10 seconds from the detection. Before powering off the
system, connect the contactor to the power cable of the outdoor unit and open
the contactor. For the connection procedures, specifications, and installation
location of the contactor, refer to the manual of the outdoor unit.
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
malfunction 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.
Incomplete grounding may cause a risk of electric shock.
Caution:
•
Never measure the insulation resistance of the terminal block for any
control cables.
•
Incomplete purging of the air in the system, closing of the valves upstream
or down stream of the pump etc. may cause the pump to operate with no
water flow and thus lead to pump failure.
•
Ensure that the power is off when replacing a pump. Do not remove or
attach the pump connector with the power on. Otherwise pump will break.
After turning off the power, wait 10 minutes before commencing work.
Low to mid-range
Tendency
temperature water system
Recirculating
water
Make-up
Corrosive
[20<T<60°C]
water
[68<T<140°F]
7.0 – 8.0
7.0 – 8.0
30 or less
30 or less
[300 or less]
[300 or less]
(mg Cl-/ℓ) 50 or less
50 or less
/ℓ) 50 or less
50 or less
2-
50 or less
50 or less
/ℓ)
3
/ℓ) 70 or less
70 or less
3
/ℓ) 50 or less
50 or less
3
/ℓ) 30 or less
30 or less
2
(mg Fe/ℓ) 1.0 or less 0.3 or less
(mg Cu/ℓ) 1.0 or less 0.1 or less
not to be
not to be
(mg S
/ℓ)
2-
detected
detected
/ℓ) 0.3 or less 0.1 or less
+
4
(mg Cl/ℓ) 0.25 or less 0.3 or less
/ℓ) 0.4 or less 4.0 or less
2
6.0 – 7.0
–
Earth leakage
Wire size
breaker
20 A 30 mA
1.5 mm
0.1 s or less
Scale-
forming
2
15
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