Scale Deposits
Introduction
Scale forms when minerals in boiler water settles out on the inside of boiler surfaces. Scale accumulates when improperly treated water comes in contact with the hottest parts of the boiler. The most common components of scale are lime, magnesium and iron oxides (rust). Scale acts as an insulator, preventing the heat from the burner to reach the water. This increases boiler flue temperature (more heat is lost up the stack) and can lead to damage to the boiler.
Energy Losses From Scale Deposits
The following table is an estimate of how scale effects fuel usage:
|
Scale Thickness (Inches) |
Additional Fuel Usage (Percentage) |
|
1/32 |
8.5% |
|
1/25 |
9.3% |
|
1/20 |
11.1% |
|
1/16 |
12.4% |
|
1/8 |
25.0% |
|
1/4 |
40.0% |
|
3/8 |
55.0% |
|
1/2 |
70.0% |