Water Pipe Installation; Precautions During Installation; Insulation Installation - Mitsubishi Electric CITY MULTI PWFY-P100VM-E-BU Manuel D'utilisation

7. Water pipe installation

• Before a long period of non use, purge the water out of the pipes and thoroughly
let them dry.
• Use a closed water circuit.
• When the unit is in cooling mode, add brine to the circulating water to prevent it
from freezing.
• To use brine in the system, DipSW 1-10 must be set to ON.
• When installed in a low-ambient temperature environment, keep the water circu-
lating at all times. If that is not possible, purge the water out of the pipes com-
pletely or fill the water pipes with brine.
• Do not use the water used for this unit for drinking or food manufacturing.
• Do not use steel pipes as water pipes.
Model
PWFY-P100VM-E-BU
PWFY-P140VM-E1/E2-AU
*1 When the attached expan-
sion joints are installed.

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.
• On the PWFY-P140VM-E1/E2-AU model, install the expansion joint (accessory)
to the inlet (after installing the strainer) and outlet.
Example of unit installation (using water piping)
[Fig. 7.1.1] [Fig. 7.1.2] (P.2)
A Close valve
C Water outlet
E Y-type strainer
G Expansion joint
• In order to protect the unit, consider the water circuit design that uses the water
circuit parts such as those shown in [Fig. 7.1.3] and [Fig. 7.1.4].
Single system sample
[Fig. 7.1.3] (P.3)
Multiple system sample
[Fig. 7.1.4] (P.3)
1 PWFY-P140VM-E1/E2-AU or PWFY-P100VM-E-BU
2 Strainer
3 Flow Switch (PWFY-P140VM-E1/E2-AU ONLY) *3
4 Shut off valve *1
5 Temperature gauge *1
6 Pressure gauge *1
7 Deaerator (Air separator) *1
8 Air vent *1
9 Safety valve *1
0 Expansion tank (closed type) *1
a Buffer vessel (if necessary) *1 *2
b Drain valve *1
c Backflow preventer *1
d Antivibration sleeve *1
10
Water inlet Water outlet
PT 3/4 Screw PT 3/4 Screw
PT 1 Screw*1 PT 1 Screw*1
B Water inlet
D Refrigerant piping
F Drain pipe
e Fix speed pump *1
f Dirt separator (if necessary) *1
g Tank, plate heat exchanger or low-loss header *1,*2
*1 These items are field supplied.
*2 Water volume (= a+g) is complied with Fig.7.1.5 per PWFY-P140VM-E1/
E2-AU
*3 As for flow switch setting, please refer to "7.4 Pump interlock"
A Primary
C Water Supply
Note:
The figure above shows a sample water circuit. This circuit is provided only as a
reference, and Mitsubishi Electric Corporation shall not be held responsible for
any problems arising from the use of this circuit.
[Fig. 7.1.5] (P.4)
A Water volume limitation [L]
C Available water volume area

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-P140VM-
E1/E2-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.4)
A Heat insulation material (accessory)
B Inject with caulking material
B 2ndary (Depend on site)
B Total hardness [mg/L]