Midea LSBLG1120/MCFN, Technical & Service Manual, Page: 86 / 97

Flooded type water cooled screw chiller (PCB Control) MCAC-CTSM-2012-11
86
Appendix 2: Requirement for cleaning and maintenance
Water quality Scale Corrosion Remark
1 PH ≤ 6 Acid water Hard Strong
Generates insoluble
CaSO
4
2 PH ≥ 8 Alkali water Soft ——
Soft fluid deposit may be
caused by ions iron or
aluminum
3
Water with much Ca
2+
and
Mg
2+
Hard ——
Easily generates hard
scale.
4 Water with much Cl
-
Dirt Ultra-strong
Corrosive to copper and
iron.
5
Water with much SO
4
2-
and
SiO
2
2-
Hard Strong
Generates hard CaSO
4
and CaSiO
2
6
Water with much Fe
3+
Large quantity,
hard
Strong
Generates deposits
Fe(OH)
3
and Fe
2
O
3
7 Odorous water Large quantity Ultra-strong
Generates sulfide,
ammonia and marsh gas,
especially H
2
S which has
great corrosion to copper.
8
Water with organic
substance
Large quantity —— Easily generates scale
9
Exhaust gas from auto,
chemical factory, plating
factory, sewage plant,
ammonia refrigeration plant
and fiber factory
Strong
Copper tubes of condenser
may be eroded and
perforated.
10
Dusty places such as plastic
plant
Large quantity
11 Sulfurous gas in the air Ultra-strong
12
Natural pollution such as
damp air near the coast or
insects in the field goes into
cooling tower.
Large quantity
Strong
Cycle under normal temp. (A):
(Capacity of co Capacity of pipe+ Capacity of container)×1/3(Thickness of detergent 33%)
Cycle under normal temp. (B):
(Capacity of flume of cooling tower+ Capacity of co Capacity of pipe)×1/10(Thickness of
detergent 10%)
In case doing cleaning after the unit stops, the capacity of flume of cooling tower can be 1/2 or 1/3 of
rated value; if doing cleaning as the unit is running, the capacity should achieve rated value.
Precautions on usage of detergent
When doing cleaning, please wear rubber gloves and do not expose your skin or your clothes to the
detergent. In case touching the detergent, please wash it with clean water.
The container for detergent should be made of plastic or glass rather than lead. The used detergent
should be neutralized with lime or soda before draining
Detergent is harmful to human; please keep it away from children.
Turn on the unit after cleaning to ensure it is clean. If necessary, please do cleaning again.