Maintenance Method Of Water Quality - Hitachi RCUE40AG2 Service Manual

Maintenance
Dissolved oxygen
−
It is an oxygen gas dissolved in water and is a great factor to promote the corrosion. Regarding copper
corrosion, possibility of corrosion is increased in dissolved oxygen volume of 5~15 (ml/l), and is decreased in
greater or less value than that.
Remarks: Oxygen consumption, all hardness and calcium hardness Remarks: Oxygen consumption, all hardness and calcium hardness
If these values are greater, line is likely to be produced, and if they are fewer, corrosion is likely to be
caused. In the guideline presented in the table, only the upper value is limited, which is based on an idea of
prevention of line trouble and of that the corrosion can be judged by other method. Therefore, if there is no
worry about line trouble, it is better to keep these values high to prevent the possibility of corrosion.
Concretely, in chilled and warm water, if RSI is 6~7.5 (there is no worry about line problem), it is convenient
to maintain the below value to prevent the corrosion.
- Oxygen consumption (pH4.8) (mgCaCO
- All hardness (mgCaCO
- Calcium hardness (mgCaCO

6.3.3. Maintenance method of Water Quality

Quality inspection of circulation water

1. Before test run, all criteria items in the table should be checked.
2. The fi rst week after test run pH and electrical conductivity should be measured. In case of any
trouble, all items should be checked.
3. One month after test run, all items should be checked.
4. After that, water quality tendency should be captured in these 3 tests and afterward schedule should
be decided by these results. Even in the case of no trouble, pH and electrical conductivity should be
checked every month and all criteria items of water quality should be checked every half year.
Action in case of water quality trouble

When the result of periodical inspection recognises some troubles in water quality, those actions as similar to
the following should be taken according to the situation.
1. Replace old water to new one or perform forced blow. (once a week ~ once a month)
2. Water should be treated with anti-corrosion agent or line inhibitor.
pag. 155
SMGB0003 rev.0 - 11/2006
/l) =50~100
3
/l) =50~200
3
/l) =below 150
3
6 6