Mitsubishi Electric CITY MULTI PKFY-WL NKMU-E Series Installation Manual page 9

4. Connecting water pipes
4.1.2. Water pipe installation for connection with HBC unit
1. Connect the water pipes of each indoor unit to the same (correct) end connection
numbers as indicated on the indoor unit connection section of each HBC controller.
If connected to wrong end connection numbers, there will be no normal operation.
2. List indoor unit model names in the name plate on the HBC controller control box
(for identification purposes), and HBC controller end connection numbers and
address numbers in the name plate on the indoor unit side.
Seal unused end connections using cover caps (sold separately). Not replacing on
end cap will lead to water leakage.
3. Be sure to add insulation work to water piping by covering water pipework
separately with enough thickness heat-resistant polyethylene, so that no gap is
observed in the joint between indoor unit and insulating material, and insulating
materials themselves. When insulation work is insufficient, there is a possibility of
condensation, etc. Pay special attention to insulation work in the ceiling plenum.
(Fig. 4-1, Fig. 4-2)
• Insulation materials for the pipes to be added on site must meet the following
specifications:
HBC controller -indoor unit 20 mm, 25/32 inch or more
• This specification is based on copper for water piping. When using plastic
pipework, choose a thickness based on the plastic pipe performance.
• Installation of pipes in a high-temperature high-humidity environment, such as
the top floor of a building, may require the use of insulation materials thicker than
the ones specified in the chart above.
• When certain specifications presented by the client must be met, ensure that
they also meet the specifications on the chart above.
4.Expansion vessel
Install an expansion vessel to accommodate expanded water. (circuit protection
valve set pressure: 600 kPa)
Expansion vessel selection criteria:
• The water containment volume of the HBC.
• The maximum water temperature is 60°C, 140°F.
• The minimum water temperature is 5°C, 41°F.
• The circuit protection valve set pressure is 370-490 kPa.
• The circulation pump head pressure is 0.24 MPa.
5. Leakproof the water pipework, valves and drain pipework. Leakproof all the way to,
and include pipe ends so that condensation cannot enter the insulated pipework.
6. Apply caulking around the ends of the insulation to prevent condensation getting
between the pipework and insulation.
7. Add a drain valve so that the unit and pipework can be drained.
8. Ensure there are no gaps in the pipework insulation. Insulate the pipework right up
to the unit.
9. Ensure that the gradient of the drain pan pipework is such that discharge can only
blow out.
10. HBC water pipe connection sizes
Connection size
Unit model
Water inlet Water outlet Water out Water return
O.D. O.D.
PKFY-WL18NKMU-E 22 mm, 22 mm,
27/32 inch 27/32 inch
O.D. O.D.
PKFY-WL24NKMU-E
22 mm, 22 mm,
PKFY-WL30NKMU-E
27/32 inch 27/32 inch
Pipe size
Water
volume (ℓ)
I.D. I.D.
≥ 20.0 mm, ≥ 20.0 mm,
25/32 inch 25/32 inch
2.0
I.D. I.D.
≥ 30.0 mm, ≥ 30.0 mm,
1-3/16 inch 1-3/16 inch
■ Connection of HBC (Indoor unit without valve)
* PKFY-WL·NKMU-E series has no valve
A
B
C
D D
A To outdoor unit
B End connection (brazing)
C HBC controller
D Indoor unit (without VALVE)
Note:
*1. Connection of multiple indoor units with one connection (or joint pipe)
• Total capacity of connectable indoor units: Less than 80
• Number of connectable indoor units: Maximum 3 Sets
• Selection of water piping
Select the size according to the total capacity of indoor units to be installed
downstream.
• Please group units that operate on 1 branch.
11. Please refer to the [Fig. 4-4] when connecting the water supply.
D
B
A
C
Fig. 4-4
12. Install a shut off valve and strainer in a place that is easy to operate and makes
maintenance work easy.
13. Apply insulation to the indoor unit pipework, strainer, shut off valve, and
pressure reducing valve.
14. Please do not use a corrosion inhibitor in the water system.
Water pipework is
E
screw connections
D
D D D
F
*1
E Twinning pipe (field supply)
F Up to three units for 1 branch
hole; total capacity: below 80 (but
in same mode, cooling/heating)
Fig. 4-3
E A Indoor unit
B Water pipe: Inlet
C Water pipe: Outlet
D Strainer (40 mesh or more)
(field supply)
E Shut off valve
E
(field supply)
en
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