Marine Water Heaters

[scanzel]

Sorry if this has been asked before, but has anyone out there used any of the marine water heaters. They use an electric element 750>1500 watt and and engine coolant for heating the water and a couple seen also have an additional heat exchanger for using a Webasto or Proheat for additional heating of the water. They are expensive but they seem to have the most possibilities for heating the water. All opinions appreciated. .

[belfert]

I bought the Force 10 marine water heater.  I found the best price at foreandaftmarine.com.  It has both electric and heat exchanger.  I thought I got the stainless steel model, but the price looks more like the galvanized version.

West Marine sells these now instead of the Seaward.  I did some research and a lot of boat owners like the Force 10 better than the others these days.

Do note that I have never used my water heater.  It is plumbed, but electric and heat exchanger is not hooked up yet.

[H3Jim]

I've been using the 10 gal seaward I bought from Dick Wright for several years now.  I do not yet have the heat exchanger side plumbed, but I do have the  electric hooked up.  1500 watts is a pretty good draw, so I try to turn it on only when the bus is running (bus alt charges house bats), the generator is running or I have it plugged in to shore power.

So far I have been very pleased with it

[Jeremy]

I've got a marine heater too (a Surecal in my case), but also haven't actually used it yet. Because I got a big one (70 litres) I chose not to get one with the electric heating element (heating 70 litres of water electically would take ages, but would be fine if you were plugged into shore power all the time). Instead I have got a much smaller electric water heater as well, although that complicates the plumbing a bit. The twin coil set-up in the big heater, as well of course as the tank itself, can be configured in a number of ways to run both the hot water supply and bus heating system, with heat provided by engine / Webasto / electric etc.

The cheif advantage to me was that whenever I arrive anywhere I will have a large supply of 'free' hot water (ie. heated by the engine on the journey), which with the way the tank is insulated should last quite a while, with perhaps occasional 'topping up' with the Webasto. I only envisage using the electric heater when either the big tank is cold, or I have the generator running anyway to charge batteries - but since none of it is installed yet it's all theory at the moment!

Jeremy

[TomC]

I didn't want to run any extra coolant lines (less possibility of leaks).  I have 2-10gal elec water heaters from Home Depot that now run about $230 apiece ($160 when I bought them). One is plumbed into the next with the final water heater powered through the inverter for hot water when driving (instead of the heat exchanger).  It has been trouble free.  Only down side is when dry camping, have to run the generator to heat the water in the morning, since that's when we take our showers.  Good Luck, TomC

[donnreeves]

I have an 11 gal that I got from West marine.It is electric with a heat exchanger that I run off the Pro-Heat.I had to add an aquastat to control the water temp when on the Pro-Heat.It works but takes over an hour to recover. Two hours to go from 60* up to 130*.I added a flat plate heat exchanger to preheat the water when the Pro-Heat is running.That brings the water temp to 100* before it enters the water heater,and seems to provide an endless supply.On electric it's still slow.
Donn

[Sean]

We have the 12-gallon Seaward unit, and we never run out of hot water.  (Force-10 is probably a tad higher quality -- we bought at West Marine, which used to carry both.)

We have the heat exchanger plumbed into our hydronic heat system.  This system is in turn heated by another heat exchanger off the engine coolant, so we get all the free hot water (and domestic heat) we need when we drive.  For this reason, we usually shower in the evening when we are traveling.

When we are parked away from hookups (which is most of the time), we either run our Webasto in the morning to get a little heat and hot water, or, if we need to charge the batteries, we'll run the generator instead.  Either way we get hot water.  Of course, if we have shore power, the hot water is automatic.

Wouldn't do it any other way.

-Sean
http://ourodyssey.blogspot.com

[Goodwin]

I have an 83 MC-9 that was converted by Custom Coach.  They routinely installed a marine hot water heater in their conversions by tapping into the engine coolant lines in the tunnel between the engine and the bus/driver heaters.  Very effiecient, as the water is 190 degrees, which effectively doubles the size of the tank.  The water is more than hot enough the next morning for a good shower.  One major caution---190 degree water will scald and burn flesh; however we have not had a problem
Bill

[Dreamscape]

This is a very interesting thread. I had not considered going marine with the hot water. I am learning so much. I need to investigate this further.
Thank You All for your invaluable input.

Happy Trails,

Paul

Dreamscape

[Jeremy]

I have an 83 MC-9 that was converted by Custom Coach.  They routinely installed a marine hot water heater in their conversions by tapping into the engine coolant lines in the tunnel between the engine and the bus/driver heaters.  Very effiecient, as the water is 190 degrees, which effectively doubles the size of the tank.  The water is more than hot enough the next morning for a good shower.  One major caution---190 degree water will scald and burn flesh; however we have not had a problem
Bill

My unit has a thermostatic mixer valve on the outlet of the tank itself, which automatically stablises the outlet water to a pre-set temperature by mixing it with cold water - so the very high temp water can never reach your taps or shower.

I may be wrong, but I have always assumed that the reason way these type of heaters / tanks are quite expensive (for what is a pretty simple device) is because they are proper certified pressure vessels - mine is a 'pressure vessel shape' anyway, and I assume that the square Seaward & Force10 types actually have a round tank inside them. This is what mine looks like:



Like TomC, I was concerned about the consquences of tapping into the vehicle's cooling system as well, but as it happens the best place on my bus to fit the tank also happened to be right next to the only place where the OEM cooling lines went from copper pipe to rubber hose.

Jeremy

[scanzel]

Jeremy who is the maker of the unit you show in the picture? I have checked out a few units made in Italy which seem to be of very good quality etc. Yes the mixing valve is a good idea because of the extra hot water and some of the units come with them, an added  on valve could also be install after.

[Jeremy]

It's a British make called Surecal - http://www.surejust.co.uk/. They make units big enough to run jacuzzis on super yachts, so I think they know what they're doing. All their stuff is made from copper, which they claim is much safer for potable water than the aluminium and stainless steel used by other manufacturers.

Jeremy