Water Treatment And Quality Control; Duct Work - Mitsubishi Electric City Multi PEFY-WP20 Installation Manual

10. HBC water pipe connection sizes
Connection size
Unit model
Water inlet Water outlet
HBC Controller
PEFY-WP20VMA
PEFY-WP25VMA Rc 3/4
PEFY-WP32VMA screw
PEFY-WP40VMA
PEFY-WP50VMA
PEFY-WP63VMA
PEFY-WP71VMA
Rc 1-1/4
PEFY-WP80VMA
screw
PEFY-WP100VMA
PEFY-WP125VMA
[Fig. 7.2.3] (P.5)
A To outdoor unit
B End connection (brazing)
C HBC controller
D Indoor unit
E Twinning pipe (field supply)
F Up to three units for 1 branch hole; total capacity: below 80 (but in same
mode, cooling/heating)
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. 7.2.4] when connecting the water supply.
[Fig. 7.2.4] (P.6)
A Indoor unit
C Water pipe: To HBC unit
D Strainer (40 mesh or more) (field supply)
E Shut off valve (field supply)
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 pres-
sure reducing valve.
14. Please do not use a corrosion inhibitor in the water system.

7.3. Water treatment and quality control

To preserve water quality, use the closed type of water circuit. When the circulat-
ing water quality is poor, the water heat exchanger can develop scales, leading
to a reduction in heat-exchange power and possible corrosion. Pay careful at-
tention to water processing and water quality control when installing the water
circulation system.

8. Duct work

• In connecting duct, insert canvas duct between unit and duct.
• Use incombustible material for duct parts.
• Provide full insulation to inlet duct flange and outlet duct to prevent condensation.
• Be sure to change the position of air filter to the position where it can be serviced.
[Fig. 8.0.1] (P.6)
<A> In case of rear inlet
<B> In case of bottom inlet
A Duct
C Access door
E Ceiling surface
G Leave distance enough to prevent short cycle
• Procedure for changing the rear inlet to the bottom inlet.
[Fig. 8.0.2] (P.6)
A Filter
1. Remove air filter. (First remove filter lock screw.)
2. Remove the bottom plate.
3. Fit the bottom plate to the rear of the body. [Fig. 8.0.3] (P.6)
(Position of lug-holes on the plate are different from those for rear inlet.)
When the plate is attached
on the rear side, it exceeds
the height of the rear body
panel.
Replicate the plate along
the slit when there is not
enough room above for the
entire unit.
Pipe size
Water
Water out Water return volume (ℓ)
Inner Inner
Rc 3/4
diameter diameter
screw
≥ 20 mm ≥ 20 mm
Inner Inner
Rc 1-1/4
diameter diameter
screw
≥ 30 mm ≥ 30 mm
B Water pipe: From HBC unit
B Air inlet
D Canvas duct
F Air outlet
B Bottom plate
• Removing of foreign objects or impurities within the pipes.
During installation, make sure that foreign objects, such as welding frag-
ments, sealant particles, or rust, do not enter the pipes.
• Water Quality Processing
10
1 Depending on the quality of the cold-temperature water used in the air-
0.7
conditioner, the copper piping of the heat exchanger may corrode.
1
Regular water quality processing is recommended.
If a water supply tank is installed, keep air contact to a minimum, and
1.8
keep the level of dissolved oxygen in the water no higher than 1mg/ℓ.
2.0
2 Water quality standard
2.6
3.0
Items
pH (25°C) [77°F]
Electric conductivity
Chloride ion
Sulfate ion
Acid consumption (pH4.8)
Total hardness
Calcium hardness
Ionic silica
Iron
Copper
Sulfide ion
Ammonium ion
Residual chlorine
Free carbon dioxide
Ryzner stability inde
Reference: Guideline of Water Quality for Refrigeration and Air Condi-
tioning Equipment. (JRA GL02E-1994)
3 Consult with a specialist about water quality control methods and calcula-
tions before using anti-corrosive solutions.
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, adjust water quality before replac-
ing the unit.
4. Fit filter to the underside of the body.
(Be careful of which side of the filter to fit.) [Fig. 8.0.4] (P.6)
[Fig. 8.0.4] (P.6)
C Nail for the bottom inlet
Caution:
• Inlet duct of 850 mm or more should be construted.
To connect the air conditioner main body and the duct for potential
equalization.
• To reduce the risk of injury from metal sheet edges, wear protective
gloves.
• To connect the air conditioner main body and the duct for potential
equalization.
• The noise from the intake will increase dramatically if intake is fitted
directly beneath the main body. Intake should therefore be installed as
far away from the main body as possible.
Particular care is required when using it with bottom inlet specifica-
tions.
• Install sufficient thermal insulation to prevent condensation forming on
outlet duct flanges and outlet ducts.
• Keep the distance between the inlet grille and the fan over 850 mm.
If it is less than 850 mm, install a safety guard not to touch the fan.
• To avoid electrical noise interference, do not run transmission lines at
the bottom of the unit.
Low to mid-range
temperature water system
Recirculating
water
Make-up
[20<T<60°C]
water
[68<T<140°F]
7.0 ~ 8.0 7.0 ~ 8.0
(mS/m) (25°C) [77°F] 30 or less 30 or less
(µ s/cm) (25°C) [77°F] [300 or less] [300 or less]
(mg Cl-/ℓ) 50 or less 50 or less
(mg SO4 2- /ℓ) 50 or less 50 or less
50 or less 50 or less
(mg CaCO /ℓ)
3
(mg CaCO /ℓ) 70 or less 70 or less
3
(mg CaCO /ℓ) 50 or less 50 or less
3
(mg SiO /ℓ) 30 or less 30 or less
2
(mg Fe/ℓ) 1.0 or less 0.3 or less
(mg Cu/ℓ) 1.0 or less 0.1 or less
not to be not to be
(mg S 2- /ℓ)
detected detected
(mg NH + /ℓ) 0.3 or less 0.1 or less
4
(mg Cl/ℓ) 0.25 or less 0.3 or less
(mg CO /ℓ) 0.4 or less 4.0 or less
2
6.0 ~ 7.0 –
D Nail for the rear inlet
Tendency
Scale-
Corrosive
forming
13