Precautions During Installation; Insulation Installation; Water Processing And Water Quality Control - 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 unit, a strainer on the
circulating water inlet is necessary.)
• Install a suitable air vent on the water pipe. After sending water through the pipe,
be sure to vent the excess air.
• Condensed water may form in the low-temperature sections of unit. Use a drain-
age 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 maximum
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 water.
• 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.
• Wrap the sealing tape as follows.
1 Wrap the joint with sealing tape in the direction of the threads (clockwise), and
do not let the tape run over the edge.
2 Overlap the sealing tape by two-thirds to three-fourths of its width on each
turn. Press the tape with your fingers so that it is pressed firmly against each
thread.
3 Leave the 1.5th through 2nd farthest threads away from the pipe end
unwrapped.
• 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.
2 Water quality standard
Items
pH (25 ˚C)
Electric conductivity (mS/m) (25 ˚C)
(μ s/cm) (25 ˚C)
Chloride ion
Sulfate ion (mg SO4
Standard
items
Acid consumption (pH4.8)
(mg CaCO
Total hardness (mg CaCO
Calcium hardness (mg CaCO
Ionic silica
Iron
Copper
Sulfide ion
Refer-
ence
Ammonium ion (mg NH
items
Residual chlorine
Free carbon dioxide
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 con-
trol methods and water quality calculations before using anti-corrosive solu-
tions 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 sufficiently
before replacing the unit.
8
Lower mid-range temperature water system
Water Temp.
Recirculating water
7.0 ~ 8.0
30 or less
[300 or less]
(mg Cl /ℓ) 50 or less
-
/ℓ) 50 or less
2-
50 or less
/ℓ)
3
/ℓ) 70 or less
3
/ℓ) 50 or less
3
(mg SiO /ℓ) 30 or less
2
(mg Fe/ℓ) 1.0 or less
(mg Cu/ℓ) 1.0 or less
not to be
(mg S /ℓ)
2-
detected
/ℓ) 0.3 or less
+
4
(mg Cl/ℓ) 0.25 or less
(mg CO /ℓ) 0.4 or less
2
–
• On the PWFY-P200VM-E1-AU model, install the expansion joint (accessory) at
the inlet after installing the strainer, and outlet.
Example of unit installation (using water 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-E1-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 water circuit. 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 water, the copper piping of the heat exchanger
may become corroded. We recommend regular water quality processing.
Water circulation systems using open heat storage tanks are particularly
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/ℓ.
Higher mid-range temperature water system
60 ˚C Water Temp. > 60 ˚C
Make-up water 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
– –
B Water inlet
D Refrigerant piping
F Drain pipe
Tendency
Make-up water Corrosive Scale-forming
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
–