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7.3. Water processing and water quality control
To preserve water quality, use the closed type 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 of the heat exchanger. Please pay careful attention to water processing and water quality control when installing the water cir-
culation 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 water, the copper piping of the heat exchanger may become corroded. We recommend regular water quality processing.
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)
Electric conductivity (mS/m) (25 ˚C)
(μ s/cm) (25 ˚C)
Chloride ion
Sulfate ion
(mg SO4
Standard
items
Acid consumption (pH4.8)
(mg CaCO
Total hardness
(mg CaCO
Calcium hardness
(mg CaCO
Ionic silica
Iron
Copper
Sulfide ion
Refer-
ence
Ammonium ion
(mg NH
items
Residual chlorine
Free carbon dioxide
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), 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.
7.4. Pump interlock
To perform test run before the pump interlock circuit is completed, short circuit the
terminal block TB142A (IN1), and then perform test run.
The 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 TB142A (IN1) that can be found on the unit.
[Fig. 7.4.1] (P.4)
In the system including PWFY-P140VM-E1/E2-AU, the circulating water may freeze,
and result in a unit malfunction. Perform the electrical work as shown in [Fig. 7.4.2] to
prevent water from freezing.
[Fig. 7.4.2] (P.4)
A Fuse
B Coil of the magnetic contactor for heat source water pump
C Double pole contact of the magnetic contactor for heat source water pump
D Circuit breaker
E Water pump
F Bimetal break contact
When installing the unit, be sure to install the supplied flow switch on the water outlet
side of the unit and connect the wire to IN1 of TB142A on the unit.
If the flow switch is not installed, the unit will emit the error signal (2100: Inter-
lock error) and not operate.
* A short-circuit wire is supplied, but it is only for test run.
1 Remove the pipes attached to the flow switch.
Note: The unit is shipped with the pipes loosely tightened.
2 Wrap seal tape around the threads at the end of the pipes, starting at the
1.5th or 2nd thread, and not over the openings. Apply two to three wraps in
the direction of the pipe threads (clockwise). Each course of the tape should
overlap the one before it by 2/3 to 3/4 the width of the tape. Run your fingers
around the threads and tape to press the tape into the threads.
Then, attach the pipes to the flow switch, holding parts A and B with a span-
ner. The maximum tightening torque is 60 N•m (611 kgf•cm).
Lower mid-range temperature water system
Water Temp.
Recirculating water
7.0 ~ 8.0
30 or less
[300 or less]
(mg Cl
/ℓ)
50 or less
-
/ℓ)
50 or less
2-
50 or less
/ℓ)
3
/ℓ)
70 or less
3
/ℓ)
50 or less
3
(mg SiO
/ℓ)
30 or less
2
(mg Fe/ℓ)
1.0 or less
(mg Cu/ℓ)
1.0 or less
not to be
(mg S
/ℓ)
2-
detected
/ℓ)
0.3 or less
+
4
(mg Cl/ℓ)
0.25 or less
(mg CO
/ℓ)
0.4 or less
2
–
Higher mid-range temperature water system
60 ˚C
Water Temp. > 60 ˚C
Make-up water
Recirculating water
7.0 ~ 8.0
7.0 ~ 8.0
30 or less
30 or less
[300 or less]
[300 or less]
50 or less
30 or less
50 or less
30 or less
50 or less
50 or less
70 or less
70 or less
50 or less
50 or less
30 or less
30 or less
0.3 or less
1.0 or less
1.0 or less
1.0 or less
not to be
not to be
detected
detected
0.1 or less
0.1 or less
0.3 or less
0.1 or less
4.0 or less
0.4 or less
–
–
3 Attach the flow switch and pipes to the water outlet in the horizontal posi-
tion.
The angle of the axis of the pipe should be less than 45 degrees.
Check the direction of the flow switch as shown in Fig. C.
4 Connect the flow switch wire to IN1 of TB142A.
PWFY-P140VM-E1/E2-AU
Set the DipSW as shown in the table below.
DipSW3-6
External output contact
ON*1
Effective when Thermo-ON
OFF
Effective when Operation-ON (Remote controller-ON)
*1 As for PWFY-P140VM-E2-AU, be sure to set Dip SW3-6 to ON. (Otherwise, unit
cannot operate.)
Be sure to turn on the power supply of the pump, since the control does not work if
the power supply of the pump is turned off.
Connect the wiring as shown in [Fig. 7.4.3].
Implement the following for a PWFY-P140VM-E1-AU (PWFY-P140VM-E2-AU are
not available.) unit that meets conditions
(1) and (2) below:
• Pump interlock
• Use of a solenoid valve kit (PAC-SV01PW-E)
Make-up water
Corrosive
7.0 ~ 8.0
30 or less
[300 or less]
30 or less
30 or less
50 or less
70 or less
50 or less
30 or less
0.3 or less
1.0 or less
not to be
detected
0.1 or less
0.3 or less
4.0 or less
–
Fig.C
Flow switch
A
B
C
C
C
205 mm
Tendency
Scale-forming
11
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