The Voyage of the Swan
  1. First, I made sure the power to the heater was off!
  2. Second, I drained the engine coolant.
  3. I didn’t have the proper Yanmar plugs to plug the ports where the two hoses from the heater system connect to the engine and didn’t feel like spending the time and money to get them. So, I simply cut one of the hoses, bent it back and connected it to the other port. I made the bend such that it was not so short it would kink, but not so long that it would flop around (picture below for our Yanmar 3JH2E). I did this in 2007 and I still haven’t bought the plugs yet!
  4. If I’d had the plugs, I could have disconnected the hoses and replaced the hose barbs with the plugs.  It’s necessary to be very careful when tightening the plugs. They are typically pipe thread (tapered). If overtightened, they can crack the casting.
  5. Now, the engine was out of the picture. I then disconnected the hoses from the expansion tank (usually in the port cockpit locker) and heater. Then I removed the hoses, heater and expansion tank (screws, nuts and bolts). I bought the appropriate end caps/plugs for the pressure drinking water hoses to plug them where they were connected to the heater. I Disconnected the electrical wires to the heater and capped them. I left the wire and drinking water hoses in place in case the next guy wants a heater (hard to imagine, but . . . )
  6. I did an engine water flush and refilled with Yanmar antifreeze/water mix and said goodbye to rusty water from the heater. I made sure that the engine had the proper water pressure cap in place. Sometimes the pressure cap is removed when a heater system is in place because the cap on the heater expansion tank serves the purpose.
Water Heater Removal
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