I special ordered the replacement unit during Defenders annual sale and then looked around the engine room trying to figure out the best way to tackle the project. There were two hot water heaters in the engine room. A small, square Isotherm unit that worked off the Generator (decommissioned last year due to leakage) and the 20 gallon Raritan unit tucked way back in the corner behind the wing engine.
The first task was to remove the Isotherm Unit, which proved a little tricky as the outside mounting bolts were very difficult to access. Perseverance paid off and once the coolant hoses were plugged and the spilled coolant was cleaned up, it was time to tackle the big unit.
The large heater had been in place for ten years, so many of the fittings were corroded and took a lot of persuasion to remove. Eventually, large pipe wrenches were able to persuade even the most stubborn fittings and I was able to just squeeze the old heater out by going over the top of the wing engine at an angle.
I hauled the new unit in, using the same serpentine and angled path, then made a quick trip to West Marine for some new fittings to replace the corroded hose adapters going to the main engine coolant. The heater was wired and plumbed up and filled with water. Of course there is always one leak (the pressure relief valve which I had torqued the piss out of), but bigger wrenches convinced even that to stop.
I turned the unit on and soon had toasty warm water again to wash my hands after cleaning up the giant mess that I had made! Hopefully, I’ll get another ten years out of the new unit before I have to tear it apart again! I’m thinking I’ll check the aluminum anode in the heater annually, just to be sure!