New Water Heater Problem-Heads up

Hello All, I recently replaced my 14 year old water heater with the exact same size (6 gal.) unit with engine heat exchanger. I am writing to give anyone about to do this a heads-up. The new unit worked fine at the dock for the winter, but when we left to head north, everyday the reset breaker on the unit would need to be reset. Only way to get hot water on the 120 volt side is to climb into engine room, remove cover on unit & reset. After talking to the manufacturer, the told me to cut the flow on the 'in' side way back & this should solve the problem, the 180 degree water is too hot for the breaker, which is 170. I said this is a defect in the unit, as 180 is standard diesel running temp. Only valve I have on the 'in' side is right at the unit & the hose feeding is 14 years old and impossible to get at without pulling the generator, so I am afraid to use this remedy. I don't want to name the manufacturer here, so I am only posting this as a FYI. I paid about a hundred bucks extra for this feature which is useless, unless I do some major plumbing.

gar said:

... I don't want to name the manufacturer here, so I am only posting this as a FYI...

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Sounds like a manufacturing screw up. Why not name the manufacturer? It sounds like this is specific to one vender. Help us out here.

Edit: It almost sounds like you have a faulty thermostat.

FWIW, according to the manual, the thermostat on our unit (and similar, from the same maker) is fixed at 140°F.

At least one model "is equipped with a thermostatically controlled high efficiency heat exchange system which will prevent the water from becoming excessively hot" and it has a resettable "high temperature limit switch". We don't have that model... and we don't use the heat exchanger function... so I don't have any direct experience with all that on this boat.

-Chris

gar,

I agree, manufacturer screwed up on over-heat limit switch; probably should have been more like 200deg F.

I recently went through a water heater rebuild and new pump and pressure tank replacement.(I can relate to limited access)
The tank had been leaking since I bought her a few years ago. It was a nice 30-yr old heavy SS tank and the heating element had rotted out. So, for about $20 and some hard work I got an almost new tank. Some pictures below.

This tank had only a 160 deg. limit switch. These are really not meant to be a "cycling" switch as it is being used. There should be, and usually is on higher end models, an adjustable temp cycling switch, as well at the 200 deg. Limit switch just in case the thermostat sticks and "runs away".

Personally, if you have 2 thermos, I would just bypass the Limit switch for now and replace it with a higher one when you get the chance. The intent of the limit switch is not to let the heater run away and start boiling and then pop plumbing connections.

BTW, I reduced my (thermostat) limit switch to 120 deg because I do not like scalding hot water coming out of the faucet; just personal preference. Higher temps are recommended for killing bacteria, but I do not use boat water for drinking and my water tank turn-over is fairly often.
Also, I down-sized the heating element to 1200 watts from 1500 to save some amps in my 30 AC system for other uses like coffee pot, microwave, battery charger and cabin heater at the same time.

gar said:

Only valve I have on the 'in' side is right at the unit & the hose feeding is 14 years old and impossible to get at without pulling the generator, so I am afraid to use this remedy.

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14 year old hose is pretty old. You might consider replacing it on your schedule rather than on its schedule. Eventually it will fail.

Can you get to the end of the hose that doesn't have a valve on it and put a valve there? Or cut the hose and put an inline valve on the valve?

I agree it's time to replace that hose some how.

We have a Raritan 1700 series water heater with the heat exchanger and have never had any problems. I would talk to another service tech with in the company (?). Something is not functioning as it should. Here's a picture of the thermostat/red reset button which are all one part.

Delta Jim: Nice plumbing job!

After making this post, I got a call-back from the mfr. rep. who told me there were some others with the same condition & they were sending me a reset breaker that should be good to 190 degrees. I will have that in about a week & will post results. For now, I am installing a gate valve at the engine on the feed hose, so I can cut off there, if I loose the hose. I am going to replace these as soon as I can. The return line is valved at the engine, so I can still isolate the engine from this this system entirely. What was so puzzling to me is that the reset button would pop on temp alone-I don't run the generator at all during the day's run. Thanks for all your replies & will post the results asap

I just saw Larry Ms post & I have the same model unit

gar said:

After making this post, I got a call-back from the mfr. rep. who told me there were some others with the same condition & they were sending me a reset breaker that should be good to 190 degrees. I will have that in about a week & will post results. For now, I am installing a gate valve at the engine on the feed hose, so I can cut off there, if I loose the hose. I am going to replace these as soon as I can. The return line is valved at the engine, so I can still isolate the engine from this this system entirely. What was so puzzling to me is that the reset button would pop on temp alone-I don't run the generator at all during the day's run. Thanks for all your replies & will post the results asap

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I was going to suggest just replacing the thermostat but I see you've got that covered.

180 degrees is very hot for domestic hot water and can scald people but when you consider the small size of our water heaters, it's more efficient to have very hot water and use less of it mixed with cold water.

You can buy and install a tempering valve external to the water heater that will automatically mix in enough cold water with the 180 degree hot water to make it safe.

I've never had an issue with 180 degree hot water or my guests aboard. I simply tell them the water is boiling that comes out of the hot side so use it very sparingly.

It works. No problems at all. I can take long showers or multiple too.

Capthead said:

I've never had an issue with 180 degree hot water or my guests aboard. I simply tell them the water is boiling that comes out of the hot side so use it very sparingly..

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I don't have a problem either but if you often (or ever) have children aboard it could be an issue.

I haven't had any children aboard yet. But grand kids are coming and......

"I recently went through a water heater rebuild and new pump and pressure tank replacement.(I can relate to limited access)"

Are you kidding me? I can only WISH I had that much room to work in! Mine sits between the engines, under the water pump, behind the battery charger and half the batteries! I have to remove more equipment than you can imagine just to work on it...

UPDATE: The manufacturer has sent me a new thermostat/with reset breaker, which I have installed. Works fine on the shore power side, but will not be able to test with engine for a while as I am having exhaust work done on my engine. I will report the result when I get to run the boat again.

I haven't had any children aboard yet. But grand kids are coming and......

Time to install an anti scald valve in the hot side of the FW system.

$100 ,or so , way cheaper than blistered body parts!



http://www.google.com/aclk?sa=l&ai=...2-US-1LF-1-Sweat-Union-Mixing-Valve-Lead-Free
Honeywell‑S... AM102‑US‑1...
$109.35
SupplyHouse...

​

1. Anti-Scald Water Mixing Valves - Honeywell
   
   yourhome.honeywell.com/.../Anti-Scald...Valves/SummaryLis...Honeywell
   
   
   Thermostatic Mixing Valve. • Designed to prevent accidental scalding. • Increases the amount of available hot water. • Anti-scald technology is low maintenance.
2. How to Install an Anti-Scald Valve - DIY Network
   
   www.diynetwork.com/.../how-to-install-an-anti-scald-valve...DIY Network
   
   
   DIY Network shows you how to top sudden shower water temperature changes by installing an anti-scald valve in your shower.

Problem solved

The manufacturer sent me a new thermostat & it works fine. I ran the boat for an hour or so at operating temp, and reset breaker held fine. The did a good job in helping & calling back to make sure all was well. They said they had a few others with the same problem. Anyone wants more info., email me direct, as I don't want to give them a 'black eye' to their brand, as it was a small number of units with this issue. Thanks again for all the replies & advise. Gary

gar said:

The manufacturer sent me a new thermostat & it works fine. I ran the boat for an hour or so at operating temp, and reset breaker held fine. The did a good job in helping & calling back to make sure all was well. They said they had a few others with the same problem. Anyone wants more info., email me direct, as I don't want to give them a 'black eye' to their brand, as it was a small number of units with this issue. Thanks again for all the replies & advise. Gary

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So, will the unit catch fire? Why not tell all of the brand name

Gary, glad it is sorted!! And thanks for what you sent, much appreciated!!

Sunchaser- No fire risk, it was just that water heater overtemp kept tripping from heat from engine (180F), which was higher than the overtemp setpoint. No fire risk from engine coolant heat, but be careful of the HOT hot water.