Installation; Service Space; Water Pipe Installation; Precautions During Installation - Mitsubishi Electric CITY MULTI PQHY-P-YLM-A1 Manual De Instalación

7. Installation

7.1. Installation
[Fig. 7.1.1] (P.2)
M10 anchor bolt. (field-supplied)
A
Check that the installation leg corners are securely supported to ensure that
B
the legs do not bend.
Check that the installation leg corners are securely supported.
C
• Attach unit tightly with bolts so that it will not fall down due to earthquakes or
strong winds.
• Use concrete or an angle bracket for the foundation.
• Vibration may be transmitted to the installation area and noise and vibration
may be generated from the floor and walls, depending on the conditions.
Provide ample vibration proofing (cushion pads, cushion frame, etc.).
• Be sure that the corners are firmly attached. If the corners are not firmly
attach, the feet of the unit may be bent.
• When using pads, be sure that the full width of the unit is covered.
• The projecting length of the anchor bolt should be less than 25 mm [1 in].
• The PQHY/PQRY-P series should not be installed at outdoor.

8. Water pipe installation

Please observe the following precautions during installation.

8.1. Precautions during installation

• The water pressure resistance of the water pipes in the heat source unit is
2.0 MPa [290 psi].
• Use the reverse-return method to insure proper pipe resistance to each unit.
• Provide some joints and bulbs around inlet/outlet of each unit for easy
maintenance, checkup, and replacement.
• To protect the heat source unit, install a strainer on the circulating water inlet
pipe within 1.5 m [4-7/8 ft] from the heat source unit.
• Install a suitable air vent on the water pipe. After flowing water through the
pipe, vent any excess air.
• Water may collect in the low-temperature sections of heat source unit. Add a
drainage pipe 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 at the point where they go through a wall.
• Secure the pipes with metal fitting, positioning them in locations to protect
pipes against breakage and bending.
• Do not confuse the water intake and outlet valves.
• This unit doesn't include a heater to prevent freezing within tubes. If the
water flow is stopped on low ambient, drain the water out.
• The unused knockout holes should be closed and the refrigerant pipes,
water pipes, power source and transmission wires access holes should be
filled with putty.
• The drain plug is installed on the back of the unit at factory for field-
connection of the drain pipes on the front of the unit. Move the plug to the
front to connect the drain pipes on the back. Verify that there are no leaks
from pipe connections.
• For installing two units, install water pipes in parallel to each other so that the
water flow rate through both units will be equal.
• Wrap sealing tape as follows.
1 Wrap the joint with sealing tape following the direction of the threads
(clockwise), do not wrap the tape 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 tight against each
thread.
3 Do not wrap the 1.5th through 2nd farthest threads away from the pipe
end.
• When installing the pipes or strainer, tighten the on-site water piping screws
to a torque of 150 N·m (1500 kg·cm), without fixing the water piping on the
unit side in place.
• When connecting heat source unit water piping and on-site water piping,
apply liquid sealing material for water piping over the sealing tape before
connection.
• Be sure to mount a strainer (more than 50 meshes) at the water inlet piping
of the unit.
24
Warning:
• Install the unit in a location strong enough to withstand its weight.
Any lack of strength may cause unit to fall down, resulting in a
personal injury.
• Have installation work in order to protect against strong winds and
earthquakes.
Improper installation may cause unit to fall down, resulting in a
personal injury.
When building the foundation, give full attention to the floor strength, drain water
disposal <during operation, drain water flows out of the unit>, and piping and
wiring routes.

7.2. Service space

• Allow for clearance space.
• In case of a single unit installation, include 600 mm or more of space for
easier access when servicing the unit from back.
[Fig. 7.2.1] (P.2)
Space for removing the control box
A
Service space (front)
C
Example of heat source unit installation (using left piping)
[Fig. 8.1.1] (P.3)
Main circulating water pipe
A
Shutoff valve
C
Refrigerant pipes
E
Water inlet (lower)
G
• In order to protect the unit, consider the water circuit design that uses the
water circuit parts such as those shown in [Fig. 8.1.2].
System example of water circuit
[Fig. 8.1.2] (P.3)
Heat source unit
A
*1*2
C Flow Switch
*1
E Temperature gauge
Backflow prevention valve
G
Flexible joint
I
Cooling tower
K
*1 These items are field supplied.
*2 As for flow switch setting, please refer to "8.4 Pump interlock".
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 for any
problems arising from the use of this circuit.

8.2. Insulation installation

As long as the temperature range of the circulating water is kept to average
temperatures year-round (30°C [86°F] in the summer, 20°C [68°F] in the winter),
there is no need to insulate the indoor piping. Insulation should be installed in
the following situations:
• On 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.
• On any drainage piping.
8.3. Water processing and water quality
control
To preserve water quality, use the closed type of cooling tower. 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. 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 air
conditioner, the copper piping of the heat exchanger may corrode.
Regular water quality processing is recommended.
Cold 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 air contact to a minimum, and keep
the level of dissolved oxygen in the water no higher than 1mg/ℓ.
Heat source unit
B
Shutoff valve
B
Water outlet (upper)
D
Y-type strainer
F
Drain pipe
H
Strainer *1
B
*1
D Shutoff valve
*1
F Pressure gauge
Pump
H
3-way valve
J
Heating tank
L