Water Heater

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Jun 1, 2005
772
Pearson 303 Robinhood, ME
First time on shore power for me. Think I blew out an element... as heater was on with tank not full (Dummy). It has a heat exchanger. Here is the question. We were motering for a couple of hours... tank was full. When we got back to the dock to use some 12 volt cold water... The cold water was HOT... The hot water was hotter than hot... What's up? The heater is a Raritan and not very accessible to work on... unless your a bat.

Any ideas or thoughts? Possible good replacement without breaking the bank.
 
Nov 6, 2006
10,216
Hunter 34 Mandeville Louisiana
If you can get at it, you can change the element and gasket.. Not an uncommon part.. but as you say, access is the key.

There should be a check valve in the cold inlet somewhere to keep the hot from traveling back to the cold side.. it may be stuck open..
 
Jan 27, 2008
3,092
ODay 35 Beaufort, NC
There is a reset button on the electrical panel inside the heater. It may have tripped due to the element overheating. Open the panel (shut off the power first for safety) and push the red button. If it clicks it was tripped like a circuit breaker.

Regarding hotter than hot, when you run your motor eventually the hot water will be the operating temperature of your engine coolant thermostat setting. So if your boat has a 160 degree thermostat your water will be that hot. Typical household hot water will never be above about 110 to 120 degrees, so hot water on a boat can be very dangerous for scalding and especially young children should be managed around it.
 
Oct 9, 2008
1,742
Bristol 29.9 Dana Point
The cold side might be warm at the faucet if the cold hose and\or sink are abutting the engine compartment. Run the cold side for 15-30 seconds to see if it cools down.

The over-hot water can be remedied in multiple ways. You can install a mixer\regulator inline. I don't know the details, it's something Mainsail recommends. Search his posts.

-Or- My boat has a bypass loop in the coolant side, so that by turning a valve I can bypass the flow of coolant around the heater, or just slow it down by partially turning the valve.

I've thought about putting a temp gauge in there somewhere so that I know when to bypass the heater, but so far I haven't truly needed it. The water has never risen to a scalding temp due to motoring. If I plan on motoring for many hours in the future then I might install one.
 
Oct 15, 2009
220
catalina 320 Perry Lake
I turned mine on this spring with no water in it. Burned out the heating element in a very short time. I replaced the element a few weeks ago. I got the element and element socket wrench from Home Depot. They cost under $20 for both. As you said, access is the key; mine is not too good but once I exposed the old element, the job was pretty easy. The old element was in tight and I used an 18" long steel bar on the element socket to break it loose. I have photos o the installation if you would like to see them.
 
Feb 26, 2004
23,353
Catalina 34 224 Maple Bay, BC, Canada
The check valve you need is a Shurflo 340-001, 1/2", available anywhere online or at a chandlery. It goes on the cold water line before the heater.

Don't run electricity to the heater for more than the 15-20 minutes it takes to heat the hot water, then turn it off.

Maine Sail recommends a thermostatic mixing valve to keep the hot water temperature down. Some have suggested that's what faucets are for, but if you have little kids, it wouldn't hurt (them!) to install one. Honeywell makes them. Do a search on thermostatic mixing valves / Maine Sail on this board and you'll find some more ideas.
 
Jun 1, 2005
772
Pearson 303 Robinhood, ME
I'll check it out this weekend. Something just does not appear right in the piping to my recollection. Thanks for your responses in advance.

Rich
 

capta

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Jun 4, 2009
5,074
Pearson 530 Admiralty Bay, Bequia SVG
One thing that can happen to the Raratan water heaters is when you are running it on engine heating, the temp can exceed the thermostat setting for the electric heating element and trip the electric element breaker (mentioned above) on the heater, not your electric panel.
 
Jun 1, 2005
772
Pearson 303 Robinhood, ME
One thing that can happen to the Raratan water heaters is when you are running it on engine heating, the temp can exceed the thermostat setting for the electric heating element and trip the electric element breaker (mentioned above) on the heater, not your electric panel.
Yup...that was the first thing I checked. It was ok.
 

capta

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Jun 4, 2009
5,074
Pearson 530 Admiralty Bay, Bequia SVG
Yup...that was the first thing I checked. It was ok.
I just remembered something;
On the Raritan website there should be instructions for testing both the element and the thermostat without removing them from the unit.
If you can't find it, I have them somewhere aboard and will dig them out if you'd like.
Just PM me.
 
Jun 1, 2005
772
Pearson 303 Robinhood, ME
Here is what I have... check valve just before the pump. From there it goes to a tee on the bottom of the tank... water into the tank or out 2 ways to the cold water in head and galley. Hot water out on top tees out to same. What I think was happening was hot water had no where to go but merge to cold water side. Galley sink is a couple feet from heater. Will tackle heater issue this fall. Just need to check to see if my water holding tank is hot too next time out!

Thanks for your responses.
 
Nov 26, 2008
1,970
Endeavour 42 Cruisin
There are 2 kinds of check valves. My cold water input into the water heater had a spring type check valve. The engine heated water was overpowering the spring. I replaced it with a "swing" type check valve. It is a simple flapper that will close off the flow completely. Works.
 
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