Notes On Corrosion - Mitsubishi Electric CMB-WP1016V-GA1 Service Handbook

[ I Read Before Servicing ]

2. Notes on corrosion

(1) Water quality
It is important to check the water quality beforehand. See table below (Circulating water/Makeup Water Quality Standards).
Standard items
Reference items
Reference : Guideline of Water Quality for Refrigeration and Air Conditioning
Equipment. (JRA GL02E-1994)
(2) Debris in the water
Sand, pebbles, suspended solids, and corrosion products in water can damage the metal pipe and heat exchanger on the
HBC controller and may cause corrosion. When installing, prevent debris from entering the water. If there is debris in the wa-
ter, perform debris removal operation after test run by cleaning the strainers inside the HBC controller. (Refer to other sections
for how to perform a test run.)
(3) Connecting pipes made of different materials
Connecting pipes used for HBC controller and indoor unit are copper alloy pipes. If steel pipes are connected tothe pipes, the
contact surface will corrode. Do not use steel pipes to avoid corrosion.
(4) Residual air
Residual air in the pipe results in water pump malfunction, noise, or water pipe corrosion in the water circuit. Ensure air is
purged before use. (Refer to other sections for how to perform air vent operation.)
HWE1410A
Items
pH (25°C[77°F])
Electric conductivity (mS/m) (25°C[77°F])
(μS/cm) (25°C[77°F])
Chloride ion (mg Cl
Sulfate ion (mg SO
Acid consumption (pH4.8)
(mg CaCO
Total hardness (mg CaCO
Calcium hardness (mg CaCO
Ionic silica (mg SiO
Iron (mg Fe/
Copper (mg Cu/
Sulfide ion (mg S
Ammonium ion (mg NH
Residual chlorine (mg Cl/
Free carbon dioxide (mg CO
Ryzner stability index
Lower mid-range
temperature water system
Recirculating
water
Make-up
[20<T<60°C]
water
[68<T<140°F]
7.0 ~ 8.0
7.0 ~ 8.0
30 or less
30 or less
[300 or less] [300 or less]
- 50 or less
/ ) 50 or less
2- 50 or less
/ ) 50 or less
4
50 or less
50 or less
/ )
3
70 or less
/ ) 70 or less
3
50 or less
/ ) 50 or less
3
/ ) 30 or less 30 or less
2
0.3 or less
) 1.0 or less
0.1 or less
) 1.0 or less
not to be not to be
2-
/ )
detected detected
+
/ ) 0.3 or less 0.1 or less
4
0.3 or less
) 0.25 or less
/ ) 0.4 or less 4.0 or less
2
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Tendency
Scale-
Corrosive
forming
GB