Water Treatment And Quality Control - Mitsubishi Electric CITY MULTI PFFY-WP-VLRMM-E Serie Installationshandbuch

[Fig. 6.2.1] (P.3)
A Locally procured insulating material for pipes
B Bind here using band or tape.
D Lap margin: more than 40 mm
F Unit side insulating material
[Fig. 6.2.2] (P.3)
A Water pipe: To HBC unit
• Insulation materials for the pipes to be added on site must meet the following
specifi cations:
HBC controller
20 mm or more
-indoor unit
• This specifi cation 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 specifi ed in the chart above.
• When certain specifi cations presented by the client must be met, ensure that
they also meet the specifi cations on the chart above.
4. Expansion tank
Install an expansion tank to accommodate expanded water. (circuit protection
valve set pressure: 600 kPa)
Expansion tank selection criteria:
• The water containment volume of the HBC.
• The maximum water temperature is 60°C.
• The minimum water temperature is 5°C.
• 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 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
PFFY-WP20VLRMM-E
PFFY-WP25VLRMM-E
Rc 3/4 Rc 3/4
PFFY-WP32VLRMM-E
screw
PFFY-WP40VLRMM-E
PFFY-WP50VLRMM-E
[Fig. 6.2.3] (P.3)
A To outdoor unit
B End connection (brazing)
C HBC controller
D Indoor unit
E Twinning pipe (fi eld 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. 6.2.4] when connecting the water supply.
[Fig. 6.2.4] (P.3)
A Indoor unit
C Water pipe: To HBC unit
D Strainer (40 mesh or more)
(fi eld 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
C Do not leave any opening.
E Insulating material (fi eld supply)
B Water pipe: From HBC unit
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
(fi eld supply)

6.3. 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
keep the level of dissolved oxygen in the water no higher than 1 mg/ℓ.
2 Water quality standard
Items
pH (25°C) [77°F]
Electric conductivity
Chloride ion
Sulfate ion
Acid consumption (pH4.8)
Total hardness
Calcium hardness
Ionic silica
Iron
Copper
Sulfi de ion
Ammonium ion
0.9
Residual chlorine
1.3
1.3 Free carbon dioxide
1.5
Ryzner stability index
1.5
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), fi rst 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) [77°F] [300 or less] [300 or less]
(mg Cl-/ℓ) 50 or less 50 or less
2-
(mg SO4 /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
2-
(mg S /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 –
Tendency
Scale-
Corrosive
forming