Product Features
• Prevent equipment damage from galvanic corrosionProduct Description
Heat exchangers, because they are typically a copper alloy, are at risk of galvanic corrosion. To combat this, many heat exchangers are fitted with a zinc anode, or "pencil anode". You will find it (or not) under a plug in the exchanger. You can replace just the pencil anode of an anode plug as easily as unscrewing the old sacrificial anode from the plug.
Some pumps, tanks, pipelines and engines also have a similar zinc rod inside to protect dissimilar metals from corrosion. Determine if your equipment is fitted with internal anodes, and check them annually.
Why do sacrificial anodes help? Any time you have two different metals that are physically or electrically connected and near seawater, they become a battery. Some amount of current flows between the two metals. The electrons that make up that current are supplied by one of the metals giving up bits of itself--in the form of metal ions--to the seawater. This is called galvanic corrosion and, left unchecked, it quickly destroys the metals.
The way we counteract galvanic corrosion is to add a third metal into the circuit, one that is quicker than the other two to give up its electrons. This piece of metal is called a sacrificial anode, and most often it is zinc.
Replacement anodes are available without purchasing plug.
| Anode Sizing Chart | |||
|---|---|---|---|
| Size NPT |
Rod Diameter |
Rod Length |
Part No. |
| 1/4" | 1/4" | 1" | AP2501 |
| 1/4" | 1/4" | 2" | AP2502 |
| 1/4" | 1/4" | 3" | AP2503 |
| 1/4" | 1/4" | 6" | AP2506 |
| 3/8" | 3/8" | 2" | AP3752 |
| 3/8" | 3/8" | 3" | AP3753 |
| 3/8" | 3/8" | 6" | AP3756 |
| 1/2" | 1/2" | 3" | AP5003 |
| 1/2" | 1/2" | 6" | AP5006 |
| 1/2" | 1/2" | 8" | AP5008 |
| 3/4" | 3/4" | 4" | AP7504 |
| 3/4" | 3/4" | 6" | AP7506 |
| 3/4" | 3/4" | 8" | AP7508 |
| 1" | 1" | 4" | AP10004 |
| 1" | 1" | 6" | AP10006 |
| 1" | 1" | 10" | AP10010 |
| 1" | 1" | 14" | AP10014 |
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