Precautions During Installation; Insulation Installation; Water Processing And Water Quality Control; Pump Interlock - Mitsubishi Electric CITY MULTI PWFY-P100VM-E-BU Manuel D'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.
• 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)
• Install the strainer at the angle of 45˚ or less as shown in [Fig.7.1.2].
• Wrap some sealing tape around the screw part to prevent water leakage.
• Install the supplied strainer at the water inlet.
• Hold the pipe on the unit side in place with a spanner when installing the pipes
or strainer. Tighten screws to a torque of 50 N . m.
• Water pipes can get very hot, depending on the preset temperature. Wrap the
water pipes with insulating materials to prevent burns.
• On the PWFY-P200VM-E-AU model, install the expansion joint (accessory) at
the inlet after installing the strainer, and outlet.
2 Water quality standard
Items
pH (25 ˚C)
Electric conductivity(mS/m) (25 ˚C)
(µ s/cm) (25 ˚C)
Chloride ion (mg Cl -
2-
Sulfate ion (mg SO4
Standard
Acid consumption (pH4.8)
items
(mg CaCO
3
Total hardness (mg CaCO
3
Calcium hardness (mg CaCO
3
Ionic silica (mg SiO
2
Refer- Iron (mg Fe/r)
ence Copper (mg Cu/r)
items
2-
Sulfide ion (mg S
+
Ammonium ion (mg NH
4
Residual chlorine (mg Cl/r)
Free carbon dioxide (mg CO
2
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.
8
Lower mid-range temperature water system
Water Temp. 60 ˚C
=
Recirculating water
Make-up water
7.0 ~ 8.0
30 or less
[300 or less]
/r) 50 or less
/r) 50 or less
50 or less
/r)
/r) 70 or less
/r) 50 or less
/r) 30 or less
1.0 or less
1.0 or less
not to be
/r)
detected
/r) 0.3 or less
0.25 or less
/r) 0.4 or less
–
Example of unit installation (using light piping)
[Fig. 7.1.1] (P.2)
A Close valve
C Water outlet
E Y-type strainer
G Expansion joint

7.2. Insulation installation

The surface temperature of the water pipe would be very high, depending on the
set temperature. Insulate the pipe to prevent burns. When operating PWFY-P100/
P200VM-E-AU with cold water, insulate the water pipe to prevent condensation.
Wrap insulation material around water pipes as shown in [Fig. 7.2.1].
• 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.
[Fig. 7.2.1] (P.2)
A Heat insulation material (accessory)
B Inject with caulking material
7.3. Water processing and water quality con-
trol
To preserve water quality, use the closed type of cooling tower for unit. 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
control 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,
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.
Higher mid-range temperature water system
Water Temp. > 60 ˚C
Recirculating water
7.0 ~ 8.0 7.0 ~ 8.0
30 or less 30 or less
[300 or less] [300 or less]
50 or less 30 or less
50 or less 30 or less
50 or less 50 or less
70 or less 70 or less
50 or less 50 or less
30 or less 30 or less
0.3 or less
1.0 or less
1.0 or less
1.0 or less
not to be not to be
detected
detected
0.1 or less 0.1 or less
0.3 or less 0.1 or less
4.0 or less 0.4 or less
– –

7.4. Pump interlock

The unit may become damaged if it is operated with no water circulating through
the pipes.
Be sure to interlock unit operation and the water-circuit pump. Use the terminal
blocks for interlocking TB142A (IN1) that can be found on the unit.
[Fig. 7.4.1] (P.2)
B Water inlet
D Refrigerant piping
F Drain pipe
Tendency
Scale-forming
Corrosive
Make-up water
7.0 ~ 8.0
30 or less
[300 or less]
30 or less
30 or less
50 or less
70 or less
50 or less
30 or less
0.3 or less
1.0 or less
not to be
detected
0.1 or less
0.3 or less
4.0 or less
–