I'm a recent owner of a 1988 Cat-30, and when I bought the boat, I was advised that the water heater system had been completely disconnected. And my brief inspection of the system seems to bear that out. There is some information in the manual, but I'd like to know if anyone here has advice on how to reconstruct the system? I'm assuming, for the moment, that I can either repair or replace the 120VAC heater.
Water Heater Plumbing
- Thread starter fhujber
- Start date
It's actually an M25XP, always helps to get its name correct.
Have a look around here:
Engines 101 - The BIGGEST & BEST collection of M25 Series Universal Engine Information on the Internet, plus some M35, too
This includes a link to the Critical Upgrades topic which has more engine information please read it too.Diesel Engine - c34.org
On the top starboard isde of the engine are the coolant connections. This is where the coolant comes & goes. If your heater is truly disconnected from the engine, you'll see a 3/8" hose, a short one. This keeps the coolant going thru the engine. This is the line that gets used to run coolant to the heater.
assuming the heater is there, pressure test it first unless you simply want to buy a new one. The electrical work is straight-forward and others have already described the plumbing to/from the engine so all that’s left are the lines from your water tank(s).
Hey,
My guess is the old water heater was disconnected because it leaks.....
Anyway, the plumbing is pretty simple. Note there are TWO water circuits. One if the domestic water system - cold water goes into the heater from the boat water tank. Hot water comes out of the heater and goes to your various taps in your boat - galley sink, head, etc. The other water system is from the engine and is used to heat the domestic water in the heater. Hot coolant comes out of the engine and goes into the water heater HEAT exchanger, not the water tank. The coolant comes out of the water heater HX and then goes to the engine heat exchanger, and then back to the engine.
Note that when you connect the engine coolant to the heater it is difficult to get all of the air out of the lines. Don't be upset if you find your engine overheating. That means you have air in the coolant lines and you may need to 'burp' the lines a number of times until you get all of the air out. There are lots of suggestions on how to do that if you use a search.
Good luck,
Barry
My guess is the old water heater was disconnected because it leaks.....
Anyway, the plumbing is pretty simple. Note there are TWO water circuits. One if the domestic water system - cold water goes into the heater from the boat water tank. Hot water comes out of the heater and goes to your various taps in your boat - galley sink, head, etc. The other water system is from the engine and is used to heat the domestic water in the heater. Hot coolant comes out of the engine and goes into the water heater HEAT exchanger, not the water tank. The coolant comes out of the water heater HX and then goes to the engine heat exchanger, and then back to the engine.
Note that when you connect the engine coolant to the heater it is difficult to get all of the air out of the lines. Don't be upset if you find your engine overheating. That means you have air in the coolant lines and you may need to 'burp' the lines a number of times until you get all of the air out. There are lots of suggestions on how to do that if you use a search.
Good luck,
Barry