Northern Lights — SP-18 Zinc Electrode Service
Maintenance · Heat exchanger zinc electrodes
From a Northern Lights operator's manual covering: M30, M38C3, M38C3F, M40C3F, M944. Check it applies to your exact model before use.
Applies to: Northern Lights M30, Northern Lights M38C3, Northern Lights M38C3F, Northern Lights M40C3F, Northern Lights M944
Procedure
- Check zinc electrodes every 250 hours; more often in warm saltwater or where electrolysis is a problem.
- Remove the zinc holder from the bottom of the exchanger to drain raw water.
- Scrape or steel brush the zinc electrode clean.
- If more than 50% of the electrode is corroded away, replace it with a new zinc.
- Reinstall zinc holders with clean threads; do not use thread sealant.
- Refill cooling system, start engine and check for leaks.
Tools required
- Steel brush Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Replace zinc if more than 50% corroded
Full service-parts list: Northern Lights M30 →, Northern Lights M38C3 →, Northern Lights M38C3F →, Northern Lights M40C3F →, Northern Lights M944 →
Source: Northern Lights operator's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.