Fun with Water Heaters!

[Christian Van H]

Hi All! Just in case you haven't dealt with this before, I thought I'd post these pics of my recent water heater replacement. It seems as though just buying a really expensive 12 gal. marine water heater isn't enough. Apparently you must also rig up a mess of expensive fittings in order to make the thing fully functional too! See the attached picture featuring an additional one way valve (to eliminate back flow into the cold water side), the Watts tempering thermostatic valve to mix hot with cold (saving hot water and reducing the risk of burns while allowing hotter in-heater temps), and a whole host of fittings to make the connections between. Looked simple enough in the store...because half of the thing was missing! End of rant...C

[JiffyLube]

How long did it take you to put it together on the bench? Did it come with all the fittings or did you have to hunt them all down?

[ggray]

My water heater, an Isotemp, has a mixer valve as you have done, but I've wondered if I could find a solenoid valve to insert in that line, controlled by a switch in the galley. That way, you could stop the mixing of cold water if you needed really hot water. This is way down on a list of future projects.

But I did install a hot water recirculation line and valve. On our catamaran, water sources and uses are spread out, so water lines are long. By opening the recirculation valve in the head for a few seconds, the cold water in the line dumps back into the tank.

[GordMay]

Originally Posted by ggray

... I've wondered if I could find a solenoid valve to insert in that line, controlled by a switch in the galley...

Yes.
Asco, IPV, and others make Two-Way Solenoid Valves (/w 12VDC coil) , suitable for domestic hot water use.

➥ ASCO Valve - ASCO Online Product Selector

➥ #SOL1-12VDC Solenoid Valve, 12 Volt DC, For Shower Timer

[Christian Van H]

Originally Posted by JiffyLube

How long did it take you to put it together on the bench? Did it come with all the fittings or did you have to hunt them all down?

Hunted, and hunted, and hunted... There are 2 - 1/2" street elbows, 1 - 1/2" street Tee, 1 - close nipple, 1 - 1/2" union, 4 - ProPex 1/2" PEX fittings, 1 - Watts tempering valve, 1 - 1/2" flap type check valve w/Teflon seat, and a small length of Wirsbo ProPex tubing w/compression rings. Over $120 worth of extras. It's a work of art!

As for the solenoid, that sounds like a neat idea. My hose run to both the galley and tub are both less than six feet, but for the larger boat, recirculating for hotter water sure makes sense. I just bought a Jabsco Sensor 5.0 freshwater pump on ebay...cant wait to see it in action. If this PEX pumbing stuff works well I'll write it up for the world to see.

OK...whose gonna be the first one with a close nipple joke?

[Chief Engineer]

Man...that thing looks like some kinda still!!!!!!!!!!!!

[Christian Van H]

Originally Posted by Chief Engineer

Man...that thing looks like some kinda still!!!!!!!!!!!!

Now you've got me thinking!

[TaoJones]

Hey, Chris, nice work on the water hearer! It actually is fun when it's all done right, huh? Your question about Qest threaded male fittings wasn't for the WH project was it?

I think you definitely qualify for the ship's plumber title. Good job!

TaoJones

[Christian Van H]

Originally Posted by TaoJones

Your question about Qest threaded male fittings wasn't for the WH project was it?

Hey Tao! Actually its the connection I might use to attach PEX to the Jabsco Sensor 5.0 freshwater pump. The pump has snap-in ports, with both 1/2" hose barb and 1/2" Qest available. I called Zurn after you posted the link, and they offered that their Qest connectors may or may not work with Wirsbo PEX tubing. NOTHING is ever easy!

BTW, the heater is a SuperStor SS-12M. The quality seems very high, with an all stainless tank, good insulation, and high quality components. Just some pieces left out...

[s/v Jedi]

Looks good Chris!

Three questions:

- have you considered a shut off valve on the hot water side instead of the check valve?

- what temp setting do you set the mixing valve on?

- how are you planning to connect the heat exchanger? (think about draining and flushing the system!)

cheers,
Nick.

[Christian Van H]

Hey Jedi! Always good to talk hardware with you! The boat has a shut-off plumbed a couple of inches from the heater inlet. Because the pump should always maintain pressure, the check valve shouldn't see much use, but should the pump be turned off or broken the galley would see hot water in the cold lines without one. As for the temp, we are gonna try 135 deg or so...that may be too wimpy for Marisa, we'll see. Currently the exchanger is just Goodyear high-miler hoses with AWAB clamps. I should probably plumb in some way other than just removing the hose to drain, huh?

[s/v Jedi]

Chris,

When you turn off the pump, you don't get hot water from cold faucet. You only get hot water when you open up the hot-water line (or hot faucet). The hot water doesn't run back out the heater's inlet because there's nothing coming into it's hot-output (vacuum).

So, a valve after the hot water output, to be closed while doing maintenance on the plumbing, would work as well.

135 degrees... sjee that must be Fahrenheit (using that nifty converter app on my iPod Touch... ;-) ah 57 degrees Celcius. That is not enough, read this: Legionellosis - Wikipedia, the free encyclopedia
In Holland (after many people died of legionella) it is now advised that hot water lines are at least 70 degrees which kills the bacteria. That translates back to 158 deg. F.

Heat exchanger; I made this really cool system using a 3-way valve. You first have to determine what the low-point is: the heater or the engine/genset. For me it was the heater. On the coolant output of the heater, I connected a 3-way valve. The common inlet connects to the water heater, the return hose to genset on one leg and a plug to the 2nd leg. I can now stop the flow by switching the valve to the closed plug. When I drain and flush, I take the plug off, insert a hosebarb+piece of hose and turn the valve halfway to quickly drain everything. After that, turn valve completely to the piece of hose connection and flush by putting the water hose in the genset coolant tank. I realize it doesn't sound exciting but if you did any flushing without a valve like that you'll notice it is really cool and almost fun to flush ;-)

cheers,
Nick.

[Cowboy Sailer]

I designed and installed solar hot water systems. Solar systems, like engine coolant heat exchangers, are capable of heating the water to dangerous temperatures. In Texas the law required temperature-tempering valves to limit the delivered temperature of hot water to 120 degrees F for systems installed in nursing homes. This is to prevent scalding accidents. The temperature of the storage tank for the hot water can be well above the safe delivery temperature. This can insure that the bacteria are killed yet there is little scalding danger. The use of the tempering valve also seems to increase the useful capacity of the hot water tank or geyser as they call them here in South Africa. (They pronounce it geezer! Then some countries call it a caliphont or something like that.)

[captain58sailin]

Originally Posted by Christian Van H

Hunted, and hunted, and hunted... There are 2 - 1/2" street elbows, 1 - 1/2" street Tee, 1 - close nipple, 1 - 1/2" union, 4 - ProPex 1/2" PEX fittings, 1 - Watts tempering valve, 1 - 1/2" flap type check valve w/Teflon seat, and a small length of Wirsbo ProPex tubing w/compression rings. Over $120 worth of extras. It's a work of art!

As for the solenoid, that sounds like a neat idea. My hose run to both the galley and tub are both less than six feet, but for the larger boat, recirculating for hotter water sure makes sense. I just bought a Jabsco Sensor 5.0 freshwater pump on ebay...cant wait to see it in action. If this PEX pumbing stuff works well I'll write it up for the world to see.

OK...whose gonna be the first one with a close nipple joke?

Sign me up for your PEX report, one of my major projects is re-plumbing, the fresh water system, as well as the drainage, I am very interested in simplifying my fresh water system, and drainage.
Thanks,
Brad

[Christian Van H]

Jedi - I hadn't thought about the vacuum stopping flow. The manufacturer recommends the check valve for some reason. Probably to add expense.
Temp wise, 70C is as hot as my tempering valve will go. Although I know all about legionairers, I have never heard this applied to the lines, only storage and heaters. 70C is gettin' kinda hot though...As for your draining and flushing setup, that sounds perfect. My heater is lower too, so it should be perfect.

captain58sailin - Will do. This stuff is fun to work with, but the jury is still out.

Hi Cowboy! - So Geezer's geezers are set to 120f, huh? We have the same law in NJ. By setting the heater hi, and running the tempering valve lower, you effectively stretch your hot water supply, just as you pointed out. BTW, it will be a great day when cruising boats come with solar hot water and power as part of their designs. Why they don't already is beyond me...