SureStor Water Heater - Thermal Breaker Tripping
Has anyone else has run into this problem with their boat's hot water
heater?The problem is that once the water is heated up by the hot engine
coolant, the 110 v. electric water heating stops working, because a
thermal overload breaker on the heater trips. The heater runs on engine heat or 110 v. The thermostat on the heater
includes a thermal breaker that trips when the tank goes above 170
degrees. The normal operating temperature of my Volvo diesel engines
is 175-180 degrees. So eventually the engine coolant heats the water above 170, and the
thermal breaker pops. Now the heater won't work on 110 v. until the
thermal breaker is reset. (This requires disassembling the panel on
the heater to get to the breaker.) Does anyone else run into this problem? Any ideas for a workaround? The heater is a SureStor SS-12M made by Advanced Heat Transfer. |
Walt
Aug 28
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| Bad and or incompetent design. I see your problem; when the tank has |
JR
Aug 28
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| well considered thoughts to the readers of rec.boats: |
Gene
Aug 28
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| I think the water heater is part of the closed cooling system. I don't think
the mixing valve would work. You did give me an idea, however. How about
putting a transmission oil cooler in line with the water heater input. You
could use the raw water pump to supply cooling water to the oil cooler. |
Jim
Aug 28
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| Thanks for all the comments. Eisboch, you must be an engineer - you
are right on top of the problem. Yes, the thermal breaker is manual reset only. Its purpose is so that
if the electric thermostat fails, the electric heater won't boil the
water and explode the system. This isn't a problem when the engine is
heating the water, as if the temperature gets up to 212 degrees the
engine will fail first. :-( I found a good tech support guy at the manufacturer, Advanced Heat
Transfer. Then I looked around on the web and found the supplier of
the thermostat assembly:
http://www.tod.com/productdetail.asp?ProductID=85 . They are available
with thermal breakers up to 200 degrees. Then I got a voicemail from the tech support guy. Looks like they are
now using 190 degree instead of 170 degree cutouts. So hopefully I
can get one from them and be good to go. If anyone else has this problem with recently made SureStor water
heaters, talk to Ron in tech support at Advanced Heat Transfer. - Walt "Eisboch" <rce@nowhere.com> wrote: |
Walt
Aug 28
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| Used to be. But the years are now producing more of a brain dead state.
But ... you know what? .... I kinda like it. Eisboch |
Eisboch
Aug 28
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| Turn off the AC breaker to your hot water heater when your engines are
running. There's no need to heat the water with electricity underway. |
Aug 28
|
| The way I read it, that won't work. The thermal overtemp switch will pop
regardless of whether electrical power is applied or not and is not the same
as the electrical thermostat switch. Sometimes the overtemp switch mounting allows some adjustment (moves up or
down on a mounting strip) to effectively raise or lower the temperature it
"sees". Perhaps there is a higher temperature switch available as well.
That's a common problem as the engine heat transfer system often heats the
water above the electrical thermostat setting. |
Eisboch
Aug 28
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| Wow. 170 is much too hot. 120 would be better and safer. Probably the
easiest solution would be to add a bypass line with a valve to control the
flow thru the water heater. |
Jim
Aug 28
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| Problem is that controlling the flow will only slow down the rate of heating
the water.
Eventually, if the engine is being run long term, it will still get up to
the 170 degrees. Another possibility is to add a mixing valve .... flows some of the engine
heat exchanger exhaust through the water heater along with a proportioned
amount of unheated water. Problem is, I don't know where to easily get the
cold water from without adding another pump. Eisboch |
Eisboch
Aug 28
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| That makes sense if the overtemp switch is mechanical and not
electrical in nature, I would definitely agree. I was visualizing a
circuit breaker that would pop at a certain temperature but wouldn't
be active unless there was AC power supplied, and assumed that the OP
might have been running a genset underway. (how else to have both AC
power and engine coolant transfer at the same time?) Obviously the system needed is one that tests for temperature above
170 degrees *and* tests for the presence of AC power and shuts off the
AC power if both are detected. Apparently Walt's hot water tank system assumes that the hot
temperature must be the result of a failed thermostat for the AC
circuit.
It's amazing how some of the simplest problems go unresolved. |
Aug 28
|
| The type of overtemp switch I am thinking of is definitely mechanical, and
come to think of it, there are some types that automatically "unpop"
(reset) once the temp drops below it's rating. Maybe changing to that type
is another solution to his problem. I know from experience that this is a
common issue because the engine heats the water to a much higher temp than
the thermostatically controlled electric element. Eisboch |
Eisboch
Aug 28
|
