Insulation Installation; Water Processing And Water Quality Control; Pump Interlock - Mitsubishi Electric CITY MULTI PQHY-P200YHM-A Manuel D'installation

Example of heat source unit installation (using left piping)
[Fig. 8.1.1] (P.3)
Main circulating water pipe
A
Shutoff valve
C
Refrigerant pipes
E
Water inlet (upper)
G
Water piping (on-site)
A
Liquid sealing material applied part
C
Heat source unit
E

8.2. 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 (30 °C in
the summer, 20 °C 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 piping.
• Any drainage piping.
8.3. 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 hea 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.
During installation, be careful 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 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/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)
Sulfate ion (mg SO4
Standard
items
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
Copper (mg Cu/ℓ) 1.0 or less
Sulfi de ion (mg S
Refer-
ence
Ammonium ion (mg NH
items
Residual chlorine (mg Cl/ℓ) 0.25 or less
Free carbon dioxide (mg CO
Ryzner stability index
Reference : Guideline of Water Quality for Refrigeration and Air Conditioning
Equipment. (JRA GL02E-1994)
3 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.
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, please adjust water quality
suffi ciently before replacing the unit.
Shutoff valve
B
Water outlet (lower)
D
Y-type strainer
F
Drain pipe
H
Sealing tape
B
Liquid sealing material
D
Lower mid-range
Tendency
temperature water system
Recirculating
water Make-up
Corrosive
[20<T<60°C] 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
/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
0.3 or less
0.1 or less
not to be not to be
/ℓ)
2-
detected detected
+ /ℓ) 0.3 or less 0.1 or less
4
0.3 or less
/ℓ) 0.4 or less 4.0 or less
2
6.0 ~ 7.0 –

8.4. Pump interlock

The heat source unit may become damaged if it is operated with no water
circulating through the pipes.
Be sure to interlock unit operation and the water-circuit pump. Use the terminal
blocks for interlocking (TB8-1, 2, 3, 4) that can be found on the unit.
In the case of a pump interlock circuit signal connection to the TB8-3, 4, remove
the short-circuit wire. Also, use pressure valve 63PW with a minimum current of
5mA or less to prevent miss detection due to poor connection.
Pump interlock cords of parts of appliances for heat source use shall not be
lighter than polychloroprene sheathed fl exible cord (design 245 IEC 57).
[Fig. 8.4.1] (P.3)
Short-circuit wire (Connected before delivery from manufacturer)
A
B Pump interlock circuit connection
[Fig. 8.4.2] (P.3)
This circuit is for interlocking of the heat source unit operation and the mater-
circuit pump.
Heat source unit
A
To next unit
C
TM1, 2 : Timer relay (closes after elapsing the set time when it is
powered, while opens promptly when it is not powered)
52P : Magnetic contactor for water circuit pump
MP : Water circuit pump
MCB : Circuit breaker
* Remove the short circuit wire between 3 and 4 when wiring to TB8.
Scale-
forming
Site control panel
B
19