Piping Direction - Mitsubishi Electric PQRY-P72TLMU-A Manual

13. INSTALLATION
<Model : PQHY, PQRY-P-TLMU-A/YLMU-A>

13-3. Piping Direction

Main circulating water pipe
Shutoff valve
Shutoff valve
Water outlet (upper)
Refrigerant pipes
Notes:
•
Install flow switch and properly wire to TB8-terminal 3-4 for
proof of flow proteciton.
•
Provide P/T" ports near piping connections to unit on supply
and return condenser water pipe.
WR2-146
1. Insulation installation
With City Multi WY/ WR2 Series piping, as long as the temperature range
of the circulating water is kept to average temperatures year-round
(29.4°C[85°F] in the summer, 21.1°C[70°F] in the winter), there is no
need to insulate or otherwise protect indoor piping from exposure. You
should use insulation in the following situations:
• Any heat source piping.
• Indoor piping in cold-weather regions where frozen pipes are a problem.
• When air coming from the outside causes condensation to form on
• Any drainage piping.
2. Water processing and water quality control
To preserve water quality, use the closed type of cooling tower for WY/
WR2. 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 of the heat exchanger. Please pay careful
attention to water processing and water quality control when installing the
water circulation system.
• Removal of foreign objects or impurities within the pipes.
• Water Quality Processing
Y-type strainer
Water inlet (lower)
Drain pipe
PQRY-P-T(S)LMU, Y(S)LMU (April 2017 Ver2)
piping.
During installation, be careful that foreign objects, such as welding
fragments, sealant particles, or rust, do not enter the pipes.
Depending on the quality of the cold-temperature water used in the
air conditioner, the copper piping of the heat exchanger may become
corroded. We recommend regular water quality processing.
Cold water circulation systems using open heat storage tanks are
particularly prone to corrosion.
When using an open-type heat storage tank, install a water-to-water
heat exchanger, and use a closed-loop circuit on the air conditioner
side. If a water supply tank is installed, keep contact with air to a
minimum, and keep the level of dissolved oxygen in the water no
higher than 1mg/ .
Water quality standard
Items
pH (25°C)[77°F]
Electric conductivity (mS/m) (25°C)[77°F]
(µS/cm) (25°C)[77°F]
Chloride ion (mg Cl
Sulfate ion (mg SO
Standard
Acid consumption (pH4.8)
items
(mg CaCO
Total hardness (mg CaCO
Calcium hardness (mg CaCO
Ionic silica (mg SiO
Refer- Iron (mg Fe/ )
ence Copper (mg Cu/ )
items
Sulfide ion (mg S
Ammonium ion (mg NH
Residual chlorine (mg Cl/ )
Free carbon dioxide (mg CO
Ryzner stability index
Reference : Guideline of Water Quality for Refrigeration and Air Conditioning
Equipment. (JRA GL02E-1994)
Please consult with a water quality control specialist about water
quality control methods and water quality calculations before using
anti-corrosive solutions for water quality management.
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, please
adjust water quality sufficiently before replacing the unit.
Lower mid-range
Tendency
temperature water system
Recirculating
Scale-
water Make-up
Corrosive
[20<T<60°C]
forming
water
[68<T<140°F]
7.0 ~ 8.0 7.0 ~ 8.0
30 or less 30 or less
[300 or less] [300 or less]
/ ) 50 or less 50 or less
-
/ ) 50 or less 50 or less
2-
4
50 or less 50 or less
/ )
3
/ ) 70 or less 70 or less
3
/ ) 50 or less 50 or less
3
30 or less
/ ) 30 or less
2
0.3 or less
1.0 or less
0.1 or less
1.0 or less
not to be
not to be
/ )
2-
detected
detected
+
0.1 or less
/ ) 0.3 or less
4
0.3 or less
0.25 or less
4.0 or less
/ ) 0.4 or less
2
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© 2017 Mitsubishi Electric US, Inc.