Installation and operation manual
22
10T7Y1B
VRV-W IV System Air Conditioner
4P347465-1A – 2013.04
13.5. Maintenance of plate heat exchanger
The performance of a plate heat exchanger may decline due to scale
accumulation. It may be damaged by freezing due to the decrease in
the flow rate. For this reason, it is necessary to carry out programmed
maintenance at regular intervals in order to prevent scale from being
generated.
Before entering the season for use, carry out the following
inspections:
Conduct a water quality test and make sure that it is within
the standard guideline.
Clean the filter.
Make sure that the water flow rate is correct.
Make sure that the operational conditions (pressure, flow
rate, outlet temperature, etc.) are normal.
Because a plate heat exchanger has a structure which does not
permit disassembling and cleaning, follow the following
procedures for cleaning:
For maintenance purposes, it is required to provide a
connection port on the water inlet and on the water outlet.
You must connect a circulation pump in between these
2 connection ports when cleaning the plate heat exchanger
with chemicals.
For cleaning scale in the plate heat exchanger, it is
recommended to use a solution with 5% diluted formic, citric,
oxalic, acetic or phosphoric acid.
Never use hydrochloric, sulphuric or nitric acid because such
solutions have a strong corrosive feature.
Make sure to provide a stop valve in front of the inlet water
pipe connection port and a stop valve after the outlet water
pipe connection port.
Connect the piping for circulation of cleaning chemicals to the
inlet piping of the plate heat exchanger. Fill a cleaning
solution of 50~60°C for a while in the plate heat exchanger.
Then, circulate the cleaning solution using a pump for
2~5 hours.
The time for cleaning depends on the temperature of the
cleaning solution or the degree of scale accumulation.
Therefore, please watch the change of the dirtiness (colour)
of the cleaning solution to determine the level of removal of
scale.
After circulating the cleaning solution, discharge the solution
from the plate heat exchanger, fill the heat exchanger with a
solution of 1-2% sodium hydroxide (NaOH) or sodium
bicarbonate (NaHCO
3
). Circulate this solution for 15-20
minutes for neutralization purpose.
After the process of neutralization has been completed, rinse
the inside of the plate heat exchanger with care using fresh
and clean water.
When using any commercially available cleaning agent,
check in advance that such agent has no corrosive features
against stainless steel and copper.
For details of the cleaning method, ask the manufacturer of
the related cleaning agent.
After cleaning has been completed, check that the unit can be
operated in a normal fashion.
14. Electrical wiring work
14.1. Precautions on electrical wiring work
WARNING
Electrical installation. All field wiring and components must
be installed by a licensed electrician and must comply with
the applicable legislation.
NOTICE
Electrical wiring work recommendations. To persons in
charge of electrical wiring work: Do not operate the unit
until the refrigerant piping is complete.
"10.4. Leak test and
vacuum drying" on page 18
. Running the unit before the
piping is ready will break the compressor.
DANGER: Electrical shock
See
"2. General safety precautions" on page 2
.
WARNING
A main switch or other means for disconnection,
having a contact separation in all poles, must be
incorporated in the fixed wiring in accordance with the
applicable legislation.
Use only copper wires.
All field wiring must be carried out in accordance with
the wiring diagram supplied with the unit and the
instructions given below.
Never squeeze bundled cables and be sure that it
does not come in contact with the non-insulated
piping and sharp edges. Be sure no external pressure
is applied to the terminal connections.
Power supply wires must be attached securely.
If the power supply has a missing or wrong N-phase,
equipment will break down.
Be sure to establish an earth. Do not earth the unit to
a utility pipe, surge absorber, or telephone earth.
Incomplete earth may cause electrical shock.
Be sure to install an earth leakage protector in
accordance with the applicable legislation. Failure to
do so may cause electric shock or fire.
Be sure to use a dedicated power circuit, never use a
power supply shared by another appliance.
When installing the earth leakage protector be sure
that it is compatible with the inverter (resistant to high
frequency electric noise) to avoid unnecessary
opening of the earth leakage protector.
As this unit is equipped with an inverter, installing a
phase advancing capacitor not only will deteriorate
power factor improvement effect, but also may cause
a capacitor abnormal heating accident due to high-
frequency waves. Therefore, never install a phase
advancing capacitor.
Be sure to install the required fuses or circuit
breakers.
Do not operate until refrigerant piping work is
completed. (If operated before completion of the
piping work, the compressor may break down.)
Never remove a thermistor, sensor, etc., when
connecting power wiring and transmission wiring.
(If operated without thermistor, sensor, etc., the
compressor may break down.)
4P347465-1A.book Page 22 Monday, August 5, 2013 2:26 PM
