We have replaced a few heat exchanger zincs. Specifically, I just put a new one in. The old zinc had disappeared so completely that it was easy to screw a new zinc into the brass nut.
The previous change was late May this year, just before launching after a winter ashore when the system had been full of fresh water with antifreeze. Thus we have a little less than 5 months on the previous zinc.
We are pretty sure the electrical system is OK. We never plug into shore power.
We plan to check the zinc monthly now.
How long do you expect the zincs to last?
BTW, we find it easy to change the zinc in the water, by closing the inlet sea **** and running the refrigeratin cooling water pump to pull a slight vacuum on the system. No drips at all.
The normal life span of these small zinc anodes is about 6 months. If you are consuming yours at a faster rate the cause is almost always electrical.
Even if you are not plugged in to shore power, you can still experience issues when tied up in a marina.
