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7. Water pipe installation
•
City Multi WR2 Series pipes are similar to other air-conditioning pipes, how-
ever, please observe the following precautions during installation.
7.1. Precautions during installation
•
Use the reverse-return method to insure proper pipe resistance to each unit.
•
To insure easy maintenance, inspection, and replacement of the unit, use a
proper joint, valve, etc. on the water intake and outlet port. In addition, be sure
to install a strainer on the water intake pipe. (In order to maintain the heat
source unit, a strainer on the circulating water inlet is necessary.)
* An example of the heat source unit installation is shown in the diagram be-
low.
•
Install a suitable air vent on the water pipe. After sending water through the
pipe, be sure to vent the excess air.
•
Compressed water may form in the low-temperature sections of heat source
unit. Use a drainage pipe connected to the drain valve at the base of the unit to
drain the water.
•
There is a water vent plug in the center of the heat exchanger water inlet head
at the middle of the unit. Use this for maintenance, etc.
In addition, do not allow any of the unit's electrical parts (such as the solenoid
valve coil or compressor power supply) to become wet.
•
Install a back flow-prevention valve on the pump and a flexible joint to prevent
excess vibration.
•
Use a sleeve to protect the pipes where they go through a wall.
•
Use metal fittings to secure the pipes, and install them so that they have maxi-
mum protection against breakage and bending.
•
Do not confuse the water intake and outlet valves.
•
This unit doesn't have any heater to prevent freezing within tubes. When the
water flow is stopped on low ambient, take out the water from tubes.
•
The unused knockout holes should be closed and the opening of refrigerant
pipes, water pipes, power source and transmission wires should be filled with
putty and so on to prevent from rain. (field construction)
Example of heat source unit installation (using left piping)
[Fig. 7.1.1] (P.3)
A Water circulation pipe
C Close valve
E Refrigerant piping
G Water inlet
I Heat exchanger unit
7.2. Insulation installation
With City Multi WR2 Series piping, as long as the temperature range of the circu-
lating water is kept to average temperatures year-round (30°C in the summer, 20°C
in the winter), there is no need to insulate or otherwise protect indoor piping from
exposure. You should use insulation in the following situations:
•
Any heat source piping.
•
Indoor piping in cold-weather regions where frozen pipes are a problem.
•
When air coming from the outside causes condensation to form on piping.
•
Any drainage piping.
7.3. Water processing and water quality con-
trol
To preserve water quality, use the closed type of cooling tower for WR2. When the
circulating water quality is poor, the water heat exchanger can develop scales,
leading to a reduction in heat-exchange power and possible corrosion of the heat
exchanger. Please pay careful attention to water processing and water quality con-
trol when installing the water circulation system.
•
Removal of foreign objects or impurities within the pipes.
During installation, be careful that foreign objects, such as welding fragments,
B Close valve
D Water outlet
F Y-type strainer
H Drain pipe
J Compressor unit
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 air-
conditioner, the copper piping of the heat exchanger may become cor-
roded. We recommend regular water quality processing.
Cold water circulation systems using open heat storage tanks are particu-
larly prone to corrosion.
When using an open-type heat storage tank, install a water-to-water heat
exchanger, and use a closed-loop circuit on the air conditioner side. If a
water supply tank is installed, keep contact with air to a minimum, and
keep the level of dissolved oxygen in the water no higher than 1mg/r.
2 Water quality standard
Items
pH (25˚C)
Electric conductivity (mS/m) (25˚C)
(µ s/cm) (25˚C)
Chloride ion
(mg Cl
Sulfate ion
(mg SO4
Standard
Acid consumption (pH4.8)
items
(mg CaCO
Total hardness
(mg CaCO
Calcium hardness (mg CaCO
Ionic silica
(mg SiO
Iron
(mg Fe/r)
Copper
(mg Cu/r)
Refer-
Sulfide ion
(mg S
ence
Ammonium ion
(mg NH
items
Residual chlorine
(mg Cl/r)
Free carbon dioxide
(mg CO
Ryzner stability index
Reference : Guideline of Water Quality for Refrigeration and Air Conditioning
Equipment. (JRA GL02E-1994)
3 Please consult with a water quality control specialist about water quality
control methods and water quality calculations before using anti-corrosive
solutions for water quality management.
4 When replacing a previously installed air conditioning device (even when
only the heat exchanger is being replaced), first conduct a water quality
analysis and check for possible corrosion.
Corrosion can occur in cold-water systems even if there has been no prior
signs of corrosion.
If the water quality level has dropped, please adjust water quality suffi-
ciently before replacing the unit.
7.4. Pump interlock
The heat source unit may become damaged if it is operated with no water circulat-
ing through the pipes.
Be sure to interlock unit operation and the water-circuit pump. Use the terminal
blocks for interlocking (TB8-3, 4) that can be found on the unit.
In the case of a pump interlock circuit signal connection to the TB8-3, 4, remove
the short-circuit wire. Also, to prevent mistaken error detection, resulting from a
poor connection, in the pressure valve 63PW, use a low maintained current of 5mA
or less.
[Fig. 7.4.1] (P.3)
A Short-circuit wire (Connected before delivery from manufacturer)
B Pump interlock circuit connection
Lower mid-range
Tendency
temperature water system
Recirculating
Scale-
Make-up
water
Corrosive
forming
water
[20<T
60˚C]
=
7.0 ~ 8.0
7.0 ~ 8.0
30 or less
30 or less
[300 or less]
[300 or less]
-
/r)
50 or less
50 or less
2-
/r)
50 or less
50 or less
50 or less
50 or less
/r)
3
70 or less
/r)
70 or less
3
/r)
50 or less
50 or less
3
30 or less
/r)
30 or less
2
0.3 or less
1.0 or less
0.1 or less
1.0 or less
not to be
not to be
2-
/r)
detected
detected
+
0.1 or less
/r)
0.3 or less
4
0.3 or less
0.25 or less
4.0 or less
/r)
0.4 or less
2
–
–
11
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