Daikin RWEYQ72PCYD Installation Manual Download Page 14

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English

[NOTES]
(1) The circle marks in the columns for corrosion or scale to develop.
(2) Corrosion has a tendency to occur when water temperature is high

(104°F (40°C) or more), and if metals with no protective coating
whatever are directly exposed to water, it would be a good idea to
take effective measures against corrosion such as adding a corro-
sion inhibitor or deterioration treatment.

(3) In a condenser water circuit that uses a closed cooling tower, the

closed circuit circulating water and makeup water must satisfy its
water quality standards for the hot water system, and passing water
and makeup water must satisfy those for the circulation type cooling
water system.

(4) The supply water must be clean tap water, industrial water or clean

underground water.
Do not use purified or softened water.

(5) The fifteen items in the table above represent typical causes of cor-

rosion and scale.

(6) Once-through water may cause corrosion.

Do not use once-through water.

7-5 Maintenance of plate-type heat exchanger

The performance of a plate-type heat exchanger may decline due to
scale accumulation. It may be damaged by freezing due to the drop of
flow rate. For this reason, it is necessary to carry out programmed main-
tenances at a regular interval in order to prevent the scale from being
generated.

Before entering the season for use, carry out the following
inspections:

1) Conduct a water quality test and make sure that it is within the

standard.

2) Clean the strainer.
3) Make sure that the flow rate is correct.
4) Make sure that the operational conditions (pressure, flow rate,

outlet temperature, etc.) are normal.

Because the plate-type heat exchanger has a structure which does
not permit disassembling and cleaning, follow the following proce-
dures for cleaning:

1) For maintenance purposes it is required to provide for a connec-

tion port on the water inlet and on the water outlet. You must con-
nect a circulation pump in between these 2 connection ports when
cleaning the plate-type heat exchanger with chemicals.
For cleaning the scale in the plate-type heat exchanger it is rec-
ommended to use a solution with 5% diluted formic, citric, oxalic,
acetic or phosphoric acid.
Never use hydrochloric, sulfuric or nitric acid because such solu-
tions have a strong corrosive feature.

2) Make sure to provide for a stop valve in front of that inlet water

pipe connection port and for a stop valve after the outlet water
pipe connection port.

3) Connect the piping for circulation of cleaning chemicals to the

inlet and outlet piping of plate-type heat exchanger. Fill the clean-
ing solution of 122-144°F (50-62°C) for a while in the plate-type
heat exchanger. Then, circulate the cleaning solution by a pump
for 2-5 hours.
The time for cleaning depends on the temperature of cleaning
solution or the degree of scale accumulation. Therefore, please
watch the change of the dirtiness (color) of cleaning solution to
determine the level of removal of scale.

4) After circulating the cleaning solution, discharge the solution from

the plate-type heat exchanger, fill the heat exchanger with a solu-
tion of 1-2% sodium hydroxide (NaOH) or sodium bicarbonate
(NaHCO

). Circulate this solution for 15-20 minutes for neutral-

ization purpose.

5) After the process of neutralization has been completed, rinse the

inner part of the plate-type heat exchanger with care using fresh
and clean water.

6) When using any cleaning agent sold in the market, check in

advance that such agent has no corrosive features against stain-
less steel and copper.

7) For details of cleaning method, ask the manufacturer of related

cleaning agent.

After cleaning has been completed, make sure that the unit can be
operated in a normal fashion.

FIELD WIRING

NOTE

• All field wiring and components must be installed by a licensed elec-

trician and must comply with relevant local and national regulations.

• The field wiring must be carried out in accordance with the wiring

diagrams and the instructions given below.

• Be sure to use a dedicated power supply circuit. Never use a power

supply shared by another appliance.

• Do not operate until refrigerant piping work is completed.

(If operated before complete the piping work, the compressor may
be broken down.)

• Never remove thermistor, sensor or etc. when connecting power

supply and transmission wiring.
(If operated with thermistor, sensor or etc. removed, the compressor
may be broken down.)

• This equipment can be installed with a Ground-Fault Circuit Inter-

rupter (GFCI). Although this is a recognized measure for additional
protection, with the grounding system in North America, a dedicated
GFCI may not be necessary.

• This product have reversed phase protection detector only works

when the product started up.

• Replace two of the three phases (L1, L2, and L3) during reverse-

phase protection circuit operation.
Reversed phase detection is not performed while the product is
operating.

• Do not run the unit by short cutting the protection device (S1PH).

If there exists the possibility of reversed phase, lose phase, momen-
tary blackout or the power supply goes on and off while the product
is operating, attach a reversed phase protection circuit locally. Run-
ning the product in reversed phase may break the compressor and
other parts.

• Attach the power supply wiring securely.

8-1 Optional parts

Cool/Heat selector
S1S .............................. Selector switch (fan, cool/heat)
S2S .............................. Selector switch (cool/heat)

NOTE

•

Use copper conductors only.

•

When using the adaptor for sequential start, refer to chapter “Exam-
ples”.

•

For transmission wiring to outside-outside transmission F1-F2,
outside-indoor transmission F1-F2, refer to chapter “Examples”.

•

For transmission wiring to the central remote controller, refer to the
installation manual of the central remote controller.

•

Use insulated wire for the power supply.

8-2 Power supply circuit and wire requirements

A power supply circuit (see table below) must be provided for connec-
tion of the unit. This circuit must be protected with the required safety
devices, i.e. a main switch, a slow blow fuse on each phase and/or a cir-
cuit breaker.

NOTE

•

Select the power supply wire in accordance with relevant local and
national regulations.

•

Wire size must comply with the applicable local and national code.

•

Specifications for local power supply and branch wiring are in com-
pliance with local cord.

Phase and

frequency

Voltage

Minimum

circuit amp.