Can't Get Heated Water from Engine Or Hot Water Heater

Ralph vaughn

Member
Nov 14, 2018
259
Atlanta Ga
Boat Info
2007 Sea Ray 290 radar & GPS, triple axle trailer. 2006 Sea Ray 280 radar & GPS & triple axle tlr
Engines
5.0 MPI closed cooling Sea Core engines & Bravo III outdrives
4.3 MPI with alpha outdrives
My hot water heater was working fine several weeks ago. The only thing I can recall doing was I drained all the water out of my boat prior to trailering it. I'm not sure but I might have turned on the hot water heater with no water in the system so the heating elements are probably toast. I cant understand why the engine is heating the water. I think I will purchase a new hot water heater. Any suggestions on where to get one at a reasonable price. Are these hot water heaters Dometic?. Also is this a challenging job to replace the hot water heater?

Thanks for everyones comments in advance.

Ralph
 
Sorry that should be I can't understand why the engines aren't heating the water.
 
If neither method is providing hot water, then your water heater may not be the problem.
A component that was causing me problems last year was the mixing valve that's attached to the water heater. I don't how your system is set up, but I would try some other trouble shooting before buying a new heater.

My heater is an Atwood which is no longer in business, in my case I found a model made by Whale that would've been a direct replacement.
 
Check the valves and make sure water is getting in to the HW heater or possibly air bound. With the water pump on and the boat filled with water, make sure all of the air is out of the heater, run the faucet, burp the heater vent a few times. Then turn on the hot water heater and see if the amp gauge jumps 10-15 amps. If so then the element is working to some degree.

Assuming the engine was up to temp and running for more then 15mins at temp, you should have hot water. That one is concerning. I would disconnect the engine from the HW heater and pressure check the heater to 30 psi and watch for leak down. It is possible that the tubes rotted or burst, which is the only explanation I can think of for the engine not heating the water if the heater is not air bound.

Changing one out, if you can get to it easily then thats one of the easiest repairs to do, the problem is getting to it usually.
 
I was also not getting any hot water at the end of the season. So I will be looking into the same thing this spring. I was able to get in and snap a pic of the heater, and it's also an Atwood. My boat is a 2004 but the heater says 2010 so it's been replaced. A new replacement is only $300 which is shocking considering how much it costs replace most things on here :eek: If it turns out to be the heater itself and not something else, it looks like it would be hard to get out without removing the starboard manifold so I'd likely do those too.

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On your shower head is a button that allows you to turn the shower on and off with the faucets open. The water on the boat never got hot after several hours of the hot water tank on. It seems the cold and hot were mixing because I had the shower button closed and the faucets open.
 
I’d seriously consider replacing your mixing valve before you replace the entire heater. It’s about $30.
If the internal check valve is stuck, it could easily cause the symptoms you describe.

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Should have a drain valve or a high pressure relief valve on your hot water heater don’t worry about what’s coming out of the faucet right now ,verify that you have hot water in the hot water heater by opening up the drain valve and feeling how hot the water is If it is not after running the engine for a while report back and we can reassess. same goes for heating the hot water with the circuit breaker on and verifying that your element is or is not burned out
 
I'd do everything to trouble shoot the heater you have vs replacing. I know if I'd replace mine one of the engines have to come out to get to it.
 
Thanks everyone. You have given me some places to start trouble shooting
 
My hot water heater was working fine several weeks ago. The only thing I can recall doing was I drained all the water out of my boat prior to trailering it. I'm not sure but I might have turned on the hot water heater with no water in the system so the heating elements are probably toast. I cant understand why the engine is heating the water. I think I will purchase a new hot water heater. Any suggestions on where to get one at a reasonable price. Are these hot water heaters Dometic?. Also is this a challenging job to replace the hot water heater?

Thanks for everyones comments in advance.

Ralph
I’m having a very similar issue except my Atwood hot water heater never worked. Running hot engine doesn’t seem to heat it up either which I thought was strange. I bought a new element and tried to replace it last year. Omg - what a disaster. Maybe they sent me the wrong element but couldn’t get it to seal and water everywhere. Like someone else mentioned trying to repair it is much cheaper than removing the engine to gain access. I’d gladly buy a new one if it wasn’t so involved to replace. I’m just trying to get into hot water. Like I do everyday at home.
 

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