What is wrong with this water heater installation?

[boatpoker]

Thanks for the tip on the hose clamps.

The T&P currently goes overboard. Isn't that better than in the bilge?

Air space under the tank. Are you saying I should shim up the tank a bit? OR is there space between the outer housing and the tank in which insulation is sandwiched? The insulation is a bit wet at the moment since the 'whale' fittings are leaking.

I agree, overboard is better.
Yes, shim up the tank by putting 1/2" (or so) cleats of non-absorptive (plastic) material under the mounting flanges. The fiberglass insulation acts like a sponge and will hold water against the tank. The water will become stagnant and corrode the aluminum tank. This is much worse in salt water but often leads to leaky tanks in as little as a year or two even in fresh water.

 

[Xsbank]

Yes, valves. If you take the engine coolant and add more loops you add more points of failure. Also, running coolant through the hot water tank runs the risk of poisoning the water supply.

 

[LarryM]

Interesting, Larry. Ok so that begs the question as to what pressure the radiator cap will allow pressure to pass through. If the HX fails in the water heater, the fresh water pump could conceivably pump water from the storage tank out through the cap on the coolant reservoir couldn't it? What pressure does an average water pump achieve?

Bligh,

Most pressure caps are rated at 10-13PSI and vent any cooling system pressure beyond that. I believe most fresh water pumps operate between 25-60PSI, so I think you might be right. The fresh water pressure could conceivably overpower the cap and bypass to the coolant reservoir. That would even happen with the engine turned off.

Who'da thunk that?

I have never heard of this happening though. Come to think of it, I've never heard of coolant in the hot water circuit either.

It pays to keep an eye on the coolant reservoir for a number of reasons.

Larry
M/V Boomarang

 

[Capt.Bill11]

Thanks for the tip on the hose clamps.

The T&P currently goes overboard. Isn't that better than in the bilge?

Air space under the tank. Are you saying I should shim up the tank a bit? OR is there space between the outer housing and the tank in which insulation is sandwiched? The insulation is a bit wet at the moment since the 'whale' fittings are leaking.

Mount it up on some squares of Dri Dek. Dri-Dek ® | Official Site | Dri-Dek ® Floor Tiles, Sheets & Rolls

 

[Capt.Bill11]

Yes, valves. If you take the engine coolant and add more loops you add more points of failure. Also, running coolant through the hot water tank runs the risk of poisoning the water supply.

I can see how this might happen. But I have never seen nor heard of it happening to anyone with an engine heated water heater. And they are very common. So I don't think the chances are very high of it being a problem.

 

[sunchaser]

Observations?

Seaward?

 

[Xsbank]

My boat had a heat exchanger that allowed me to run my heater (Hurricane - hot water) from the engine. There was also a loop to the hot water tank. The opposite occurred too, when the heater was on it would preheat the engine block and it would heat the hot water too. The builder supplied valves so that if you were at the dock/hook and not planning to run the engine, you could isolate the engine from the water tank and the heater so you would not have to run them so long and heat up a large lump of engine.

You do realize that those hot water tank coils will try to heat the engine block by thermal loop and if you can't isolate the tank with valves it will spend a long time just heating the engine block? Kind of an inefficient hot water tank.

The builder thought that running long loops of engine coolant would provide a point of failure and I agree. That's why the heat exchanger.

 

[sunchaser]

I agree, overboard is better.
.

I and many others prefer it be routed to a catch pan so you can see if it is blowing off, indicating a problem somewhere. Our catch pan is a very visible drip pan under an engine.

 

[jimbob]

I and many others prefer it be routed to a catch pan so you can see if it is blowing off, indicating a problem somewhere. Our catch pan is a very visible drip pan under an engine.

T&P valves on domestic water heaters are to relieve pressure to prevent explosions of the wh. the makers of the t&p valves restrict the # of elbows and length of pipe to keep restriction to a minimum. Over board may not be best option.

 

[bligh]

T&P valves on domestic water heaters are to relieve pressure to prevent explosions of the wh. the makers of the t&p valves restrict the # of elbows and length of pipe to keep restriction to a minimum. Over board may not be best option.

Manufacturers discourage lengths longer than 30 ft and for 90's, but it is not addressed by the UPC. Regardless, i have no 90s and the lenght is about 10 ft tp where it terminates overboard

 

[bligh]

I and many others prefer it be routed to a catch pan so you can see if it is blowing off, indicating a problem somewhere. Our catch pan is a very visible drip pan under an engine.

Im planning on drilling a 1/4 inch hole in the drain which will warn of any issues.

 

[bligh]

You do realize that those hot water tank coils will try to heat the engine block by thermal loop and if you can't isolate the tank with valves it will spend a long time just heating the engine block? Kind of an inefficient hot water tank.

Only if the water heater is on. Which it usually isnt. But ill check and see if it does actually thermo-siphon. There is not much change in elevation. If it does, i wont lose any sleep over the hit in efficiency.

 

[FF]

Missing to me is a RV style bypass setup.

To winterize this would tale many gallons of antifreez.

With the bypass it would take ZERO.

 

[boatpoker]

Missing to me is a RV style bypass setup.

To winterize this would tale many gallons of antifreez.

With the bypass it would take ZERO.

I have never winterized a potable water system. Properly designed, draining is sufficient.

 

[sunchaser]

I have never winterized a potable water system. Properly designed, draining is sufficient.

On a larger vessel with mutiple sinks, heads, ice makers, deck takeoffs, dishwashers, water makers and dual water heaters suggest one properly winterize. The cost and time is negligible in comparison to the potential damage.

 

[Capthead]

Ok, what is wrong with it?

It makes hot water...check
The engine heats it too....check
I don't have antifreeze in my shower....check
Ok, what is wrong???

 

[boatpoker]

On a larger vessel with mutiple sinks, heads, ice makers, deck takeoffs, dishwashers, water makers and dual water heaters suggest one properly winterize. The cost and time is negligible in comparison to the potential damage.

Key phrase .... "designed properly"
I've been doing for 40 years in the Great White with no problems.

 

[bligh]

Ok, what is wrong with it?

It makes hot water...check
The engine heats it too....check
I don't have antifreeze in my shower....check
Ok, what is wrong???

Well when you put it that way.....
But it is leaking even though you cant see it from the picture.

 

[FlyWright]

I've never revived a leaking water heater. They're relatively easy to replace if you have good access.

 

[sunchaser]

Key phrase .... "designed properly"
I've been doing for 40 years in the Great White with no problems.

Surprisingly, some others here have a bit of far North experience. Years ago in New York the yard where I worked made a lot of money off patching up winterization problems. Most seemed relegated to sailboats, don't ask me why.