Tions - Mitsubishi Electric City Multi PLFY-WL-VEM-E Series Installation Manual

4. Connecting water pipes
9.Hydro unit and VALVE KIT water pipe connection sizes and pipe sizes.
Pipe size
Unit model
Water out
PLFY-WL32VEM
Inner diameter
PLFY-WL40VEM
≥ 20 mm
PLFY-WL50VEM
* If the length of branched water piping on WL40 equals or exceeds 40 m, use pipes
with an inner diameter of 30 mm or larger.
* PLFY-WL·VEM Series has no valve.
A
B
C
F
D
G G
H
E E
Fig. 4-7
10. Please refer to the [Fig. 4-6] when connecting the water supply.
11. Install a shut off valve and strainer in a place that is easy to operate and makes
maintenance work easy.
12. Apply insulation to the indoor unit pipework, strainer, shut off valve, and pressure
reducing valve.
13. Please do not use a corrosion inhibitor in the water system.
Water
volume (ℓ)
Water return
1.8
Inner diameter
1.8
≥ 20 mm
1.8
A To outdoor unit
B End connection
C Hydro unit
D To main piping
E Indoor unit without valve
E´ Indoor unit with valve
F Auto air vent valve (Highest
point on the water pipe)
(supplied)
G Optional VALVE KIT
H Pipe length between indoor
E ´ E ´
unit without valve and
optional VALVE KIT is less
than 5 m.
4.4. Water treatment and quality control
To preserve water quality, use the closed type of water circuit. 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 airconditioner,
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 1mg/ℓ.
2 Water quality standard
Items
pH (25°C) [77°F]
Electric conductivity
(mS/m) (25°C) [77°F]
(μ s/cm) (25°C) [77°F]
Chloride ion (mg Cl-/ℓ) 50 or less 50 or less
Sulfate ion (mg SO4
Acid consumption (pH4.8)
(mg CaCO
Total hardness (mg CaCO
Calcium hardness (mg CaCO
Ionic silica (mg SiO
Iron (mg Fe/ℓ) 1.0 or less 0.3 or less
Copper (mg Cu/ℓ) 1.0 or less 0.1 or less
Sulfide ion (mg S
Ammonium ion (mg NH4+/ℓ) 0.3 or less 0.1 or less
Residual chlorine (mg Cl/ℓ) 0.25 or less 0.3 or less
Free carbon dioxide (mg CO
Ryzner stability inde
Reference : Guideline of Water Quality for Refrigeration and Air Conditioning
Equipment. (JRA GL02E-1994)
3 Consult with a specialist about water quality control methods and calculations
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 replacing the
unit.
Low to mid-range
temperature water Tendency
system
Recirculating
water Make-up Scale-
Corrosive
[20<T<60°C] water forming
[68<T<140°F]
7.0 ~ 8.0 7.0 ~ 8.0
30 or less 30 or less
[300 or [300 or
less] less]
-/ℓ) 50 or less 50 or less
2
50 or less 50 or less
/ℓ)
3
/ℓ) 70 or less 70 or less
3
/ℓ) 50 or less 50 or less
3
/ℓ) 30 or less 30 or less
2
-/ℓ) not to be not to be
2
detected detected
/ℓ) 0.4 or less 4.0 or less
2
6.0 ~ 7.0 –
en
7