Daikin 80PTJU, Engineeiring Data

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Installation EDUS30-900-N
36 Installation of Outdoor Units
7. HANDLING OF THE BRAZED PLATE
TYPE HEAT EXCHANGER
CAUTION
A brazed plate type heat exchanger is used for this unit. Because
its structure is different from a conventional type heat exchanger,
it must be handled in a different manner.
7-1 When designing the equipment
1.
Install the strainer (accessory) at the water inlet side adjacent to
the outside unit in order to prevent any foreign materials such as
dust, sand, etc. from entering.
2.
Depending on the water quality, scale may stick to the plate type
heat exchanger. In order to remove this scale, it is necessary to
clean it at a regular interval using chemicals. To this end, install a
gate valve in the water piping. Set up a piping connection port on
the piping between this gate valve and the outside unit for cleaning
by chemicals.
3.
For the purpose of cleaning and water drain off from the outside
unit (water draining during a long period of non-use in winter, drain-
ing upon starting of season-off), install an “air discharge plug” and
a “water draining plug” at the inlet/outlet ports of water piping. In
addition, install an “automatic air discharging valve” at the top of
riser piping or at the top of a portion where air tends to stay.
4.
Independent of the piping inlet of the outside unit, install a clean-
able strainer at a portion close to the pump piping inlet.
5.
Carry out complete cooling/thermal insulation of water piping and
outdoor dehumidification. If complete cooling or thermal insulation
has not been carried out, any damage may be caused during
severe winter due to freezing, in addition to thermal loss.
6.
When you stop operation during night or winter, it is necessary to
take measures to prevent water related circuits from natural freez-
ing in the area the ambient temperature drops below 32°F (by water
drain off, keeping the circulation pump running, warming up by a
heater, etc.) Freezing of water related circuits may result in any
damage to the plate type heat exchanger. Therefore, please take
appropriate measures depending on the circumstances of use.
(Refer to figure 7)
1.
Example of piping
2.
Water inlet piping
3.
Strainer (accessory)
4.
Air discharge plug (for joint use with cleaning port)
5.
Cleaning device
6.
Strainer for pump
7.
Automatic air discharge valve
8.
Water outlet piping
9.
Joint use with water draining plug
10.
Plate type heat exchanger
11.
Outside unit
7-2 Before starting a test run
1.
Before starting a test run, please make sure that the piping work
has been carried out in a proper manner. Especially, make sure
that the strainer, air discharge valve, automatic water supply valve,
expansion tank and cistern are positioned at their places correctly.
2.
After water has been completely filled in, first run the pump only,
and then make sure that no air has been caught in the water circu-
lation system and the water flow rate is correct. If any air has been
caught or the flow rate is not enough, the plate type heat
exchanger may freeze. Measure any water pressure loss before
and after the outside unit and make sure that the flow rate is as
designed. In case of any abnormal, stop the test run immediately
and carry out trouble shooting to resolve the trouble.
3.
Following the installation manual, carry out a test run of the outside
unit.
4.
After the test run has been completed, inspect the strainer at the
inlet piping of the outside unit. Clean it if it is dirty.
7-3 Daily service and maintenance
1.
Management of water quality
The plate type heat exchanger has a structure that does not permit
dismantling and cleaning, or replacing any parts. Please pay atten-
tion carefully to the quality of water to be used for the plate type heat
exchanger in order to prevent corrosion and sticking of scale.
The water to be used for the plate type heat exchanger should have
at least the quality as specified in the table below.
When using any corrosion prevention agent, scale depressant
agent, etc, such agent should have no corrosive features against
stainless steel and copper.
2.
Management of chilledcondenser loop water flow rate
If the chilledcondenser loop water flow rate is not enough, it will
result in the freezing damage to the plate type heat exchanger.
Check for any clogging of the strainer, any air being caught, any
reduction in the flow rate due to failure of circulation pump by mea-
suring the temperature and pressure differences at the inlet and
outlet ports of the plate type heat exchanger. If the aged difference
in the temperature or pressure has increased beyond the proper
range, the flow rate should have decreased. Stop the operation
and remove the cause before restarting the operation.
3.
Steps to be taken when a freezing protection device was activated
When the freezing protection device should be activated during
operation, remove the cause without fail before restarting the oper-
ation. If the freezing protection device has been once activated, a
partial freezing has occurred. If you restart the operation without
removing the cause, the plate type heat exchanger will be closed
and the ice cannot be melted, and in addition, the freezing process
will be repeated resulting in any damage to the plate type heat
exchanger, leading to any such accidents that the refrigerant starts
leaking or water starts entering the refrigerant circuit.
7-4 Water quality
Water quality standards for chilled water, hot water and make-up
water (4) (6)
Item (5)
Cooling water system (3)
Hot water system (2) Tendency (1)
Circulation system
Circulation
water
Make-up
water
Circulation
water
(68°F ~ 140°F)
Make-up
water
Corrosion Scale
Standard items
pH (77°F)
6.5 to 8.2 6.0 to 8.0 7.0 to 8.0 7.0 to 8.0
 
Electrical Conductivity
(mS/ft)(77°F)
Less than
24.4
Less than
9.1
Less than
9.1
Less than
9.1
 
Chloride ions
(mgcl
–
/L)
Less than
200
Less than
50
Less than
50
Less than
50

Sulfate ions
(mgSO
4
2-
/L)
Less than
200
Less than
50
Less than
50
Less than
50

Acid consumption
(pH4.8) (mgCaCO
3
/L)
Less than
100
Less than
50
Less than
50
Less than
50

Total hardness
(mgCaCO
3
/L)
Less than
200
Less than
70
Less than
70
Less than
70

Calcium hardness
(mgCaCO
3
/L)
Less than
150
Less than
50
Less than
50
Less than
50

Ionic-state silica
(mgSiO
2
/L)
Less than
50
Less than
30
Less than
30
Less than
30

Reference items
Iron (mgFe/L)
Less than
1.0
Less than
0.3
Less than
1.0
Less than
0.3
 
Copper (mgCu/L)
Less than
0.3
Less than
0.1
Less than
1.0
Less than
0.1

Sulfate ion
(mgS
2-
/L)
Shall not be
detected
Shall not be
detected
Shall not be
detected
Shall not be
detected

Ammonium ion
(mgNH
4
+
/L)
Less than
1.0
Less than
0.1
Less than
0.3
Less than
0.1

Residual chlorine
(mgCl/L) Less than
0.3
Less than
0.3
Less than
0.25
Less than
0.3

Free carbon diox-
ide
(mgCO
2
/L)
Less than
4.0
Less than
4.0
Less than
0.4
Less than
4.0

Stability index 6.0 to 7.0 — — —
 