Hot Water System Information

[Tom Madden]

I have a 2007 34ft Catalina MKII, hull number 1768.

i have been trying to find a resource that explains the operation of the hot water heating system.  there seems to be zero information in the owners manual on this system.  from reading posts on this site and reviewing my system, i can determine the system heats water by using the heat of the engine (when running) and with an electrical system (i believe) when the engine is not running.

i'd like to get a more thorough understanding of this system (e.g. flow of water to the engine and back, regulators, how the electrical system works, how the electrical system is turned on / off, etc.)

if anyone can refer me to a source of information on this i would greatly appreciate it.  thank you very much.

tom madden

[Stu Jackson]

Tom, don't know if you are aware of some of the features of this website.  We have all the boat manuals, here:  http://www.c34.org/manuals/index.htm  You get there by going to the top of this page, and click on C34 Home, use the left side index.  And thanx for identifying your boat, but your avatar gives us that info so you don't have to retype it all the time.  Thanx.  Re the hot water heater, your boat is new enough but you should be aware of this: http://c34.org/bbs/index.php/topic,3769.0.html

I'll modify that, 1997 - over ten years old - be warned...   The electrical should have a switch on the A.C. side of the panel.  All you need is 20-30 minutes to heat the water, then turn the electricity off, no need to keep it on.

No regulators on the water side.

[Ken Juul]

The manual doesn't explain it very well, I understand your confusion.  As noted there are 2 sources of heat. 

Electrical via the 120v side of the panel.  It is switched as Stu noted, obviously only works when on shore power or a generator.

The engine is the other source. You should notice two small rubber hoses attached to your engine around the thermostat housing.  I think the thermostat acts as a "switch", when it opens, the water flows from the thermostat housing thru the water heater back to the engine thru the second hose.  It can take up to about 40 minutes of motoring to get the hot water tank.

[Ron Hill]

Tom : You have a dual capable way of heating water.
1.  As mentioned, you can turn on the AC power thru a circuit breaker on your electrical panel and heat the water while you're plugged in to shore power - just like your electric water heater at home.
2.  The engine will also heat the water.  The outlet hose from the internal fresh water cooling (50%/50% water and Prestone) goes thru a hose to the water heater. Inside the water heater is a "heat exchanger" of tubing in which the 50/50 mixture passes around the water inside the heater and - heat it up.  The coolant then returns to the engine inlet of the thermostat and finally to the reservoir.

As I've mentioned before.  In an emergency when you MUST run the engine in an over heating situation - run the engine and turn on the hot water faucets to help cool the engine.  A thought