Water Treatment And Quality Control; Duct Work - Mitsubishi Electric CITY MULTI PEFY-WP25VMS1-E Installation Manual

5. Leakproof the water pipework, valves and drain pipework. Leakproof all the
way to, and include pipe ends so that condensation cannot enter the insu-
lated 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
PEFY-WP10VMS1-E
PEFY-WP15VMS1-E
PEFY-WP20VMS1-E
Rc 3/4 Rc 3/4
PEFY-WP25VMS1-E
screw
PEFY-WP32VMS1-E
PEFY-WP40VMS1-E
PEFY-WP50VMS1-E
[Fig. 7.2.3] (P.4)
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.4)
A Indoor unit
C Water pipe: To HBC unit
D Strainer (40 mesh or more)
(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.

8. Duct work

• When connecting ducts, insert a canvas duct between the main body and the
duct.
• Use non-combustible duct components.
• Install sufficient thermal insulation to prevent condensation forming on outlet
duct flanges and outlet ducts.
Caution:
• 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.
[Fig. 8.0.1] (P.4)
A Air inlet
C Access door
E Canvas duct
G Inlet grille
10
Pipe size
Water
volume (ℓ)
Water out Water return
Inner Inner
diameter diameter
screw
≥ 20 mm ≥ 20 mm
B Water pipe: From HBC unit
E Shut off valve
(field supply)
B Air outlet
D Ceiling surface
F Air filter

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.
• 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
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.
If a water supply tank is installed, keep air contact to a minimum, and
0.4 keep the level of dissolved oxygen in the water no higher than 1 mg/ℓ.
0.7
2 Water quality standard
0.9
0.9
1.0
1.0
Items
1.7
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.
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)
[300 or less] [300 or less]
[77°F]
(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 /ℓ)
2-
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 –
Tendency
Scale-
Corrosive
forming