Gree LSQWRF35VM/NaA-M Service Manual page 118

Even though water quality is under strict control, calcium oxide or other minerals will gradually
accumulate on the surface of the evaporator. Then, it will reduce the heat exchange efficiency of the
evaporator and consequently lead to poor performance of the unit.
Therefore, the pipe system should be cleaned periodically. Oxalic acid, acetic acid and formic acid can
be used as the organic cleaning agent, but the strong chloracid is not allowed as it will corrode the copper
tube of the heat exchanger and then lead to water and refrigerant leakage.
(1) Preparation of materials and tools
Several bags of environmental friendly scale remover, or similar cleaning liquid.
(2) Cleaning instructions
1) Estimate the required amount of scale remover in accordance with the system water volume and
severity of scailing.
2) Add the scale remover to the water tank and the scale remover.
3) Start through the contact the water pump every 10 minutes and spread the scale remover in water
more quickly and widely.
4) After that, follow the steps below.
• Let the water pump run for another 1-2 hour(s).
• 1-2 hours later, change the cleaning solution to anti-rusting agent. Then, drain the water system
and check the water quality. If water is cloudy, then it indicates the cleaning effect is satisfactory.
• Open the water inlet to see if scale on the shell and tube has been removed. If not, clean the
shell and tube separately again by the skilled serviceman and then rinse them. If there is still
sand, scale and other foreign matters at the bottom of the shell and tube, let cleaning solution in
from the inlet pipe and then let the foul water out through the drain outlet.
• Fully charge the water system and let it run for another 1-2 hour(s).
• Stop the unit to drain up waste solution. If impossible, drain it with making up water at the same
time until all waster solution has been drained out completely (at this time water is transparent
and PH is 7).
• Repeat steps last two steps above.
• Clean or change the filters in the water system.
• See if the difference between the entering and leaving water temperature is improved.
• Although the cleaning agent is innocuous, but care also should be taken not to let it spill into eyes.
• The serviceman with injuries on the hand is not allowed to take this task.
Before and after cleaning, observe the running status of the unit, summarize the cleaning effect and
record the running parameters.
Cleaning of the finned heat exchanger
◆
In order to keep fins work efficiently, be sure there are no leaves, cotton wool, insects, and other
contaminants on the outer layer of fins, or they would lead to more energy consumption and high
discharge pressure. Generally, fins should be cleaned after the unit has run for 6-12 months, or more
frequently when the environment is polluted more seriously.
Unit Installation
NOTE
114