Instantaneous water heaters

Thanks Bruce

I'd planned to mount the Rinnai externally, although they do have and internal unit.

The Suburban and the Rinnai weigh about the same. But the storage types mean you have to carry around 15-22kg of water which is not easy to drain out.
Hence the attraction to the Rinnai - provided that they don't fall apart.

I'm trying to save a bit of weight wherever I can. The Truma is a bit lighter than the suburban and may be an option.

Keith

Quite a lot of boats use flueless hot water services, I don't thnik that you find that HWS run for long enough periods to cause a risk, unlike flueless heaters, of course.

One would have to ask in relation to this question?

How much gas and how much water do you intend to carry

Geoff, the three women in the family have refused any more long tours off the grid unless I can lay on a decent indoor shower. The camper is a an all solid unit with raisable roof and a pullout bed - rather like the Kimberley Karavan, but all made from honeycomb epoxy composite. It's a project that I'm doing as much for the pleasure of it as anything else.

So we'll travel as light as possible and fill the tanks as commonsense dictates. There will be a 50 litre day tank with another 250 litres or so capacity in auxiliary talks - all under the floor. The setup will allow us to pump up river water into an auxiliary tank, throw in some purification chemicals and then pump through filters into the day tank the next day.

Gas will be two 4.5 or 9.0 kg cylinders located in a locker so that they don't freeze up on winter nights. I still have some homework to do on gas supply and consumption.

I'm trying to watch every kilo so that I don't end up with a 2 tonne camper. The difference between the lightest and heaviest option among all the appliances, windows and so on can easily add a couple of hundred kilos or more. Am aiming for 1350 Kg dry weight.

Hi Keith /Bruce
Just a correction on the flueless heater, Rinnai do infact make some heaters in their range as a flued model ,the one that i have installed many of is the HD2OO model.
i wouldn't be installing one a van as i think that with all their electronic components and gas burner designs etc i think they would eventually fail. Also th e other 2 issues is that you will require 240volts for the heater to operate and need a pump that can deliver water at a min of 160kpa water pressure or else they won't even deliver cold water let alone hot water, For a van i would stick to a type that is RV specific,maybe even a diesel type. and i would not touch one of the import types that someone else mentioned if it does not include some form of AGA approval.
Rags

Hi Keith

Sounds like you have a project and a half.
We looked at the K karavan and decided it was a little small for our needs.
But I do like the concept they have.
The honeycomb composite will sure reduce weight and not skimp on strength.
A similar style to the walls of our van. Fiberglass and foam sandwich. Strength without the weight and really great insulation.... For both Heat and Cold.

I sure do understand the ladies concerns regarding a shower.

It was a bit of a tongue in cheek comment as well as I know from experience that women are not adversed to having slightly longer showers than us guys.
wet hair, shampoo, rinse, conditioner, rinse. condition again and rinse. It all takes water. and time.
So I am sure the 250 lits of water will do for a period of time.

Prior to the van we had a K kamper and as a carry over from my tenting days the 1st thing I did was to re-plumb the Tyne shower.
Uses a heat exchanger and still have it installed. Have a 90 lit tank I fit as required (no van) and am able to heat up this in about 30 mins driving.

But alas now we have the (home) creature comforts and that is hardly used.
We have a small gas heater installed and that seems to heat all the water we need in about the same time.

I will keep an eye out for the finished product.

Instant hotwater heaters and my understanding is they require a lot of BTUs to raise the water temp in a short period of time. We have one fitted here where we live and when it starts there is a lot of heat involved in making hot water. And a lot of that seems to heat the rear of the premises too.
I think the better option may be to have some form of storage heating option.
An empty tank that is able to be filled as required and then heated from a small gas heater or from some form of solar (black hose on the ground) simple and cheap in its concept. cold water in hot water out.
Then just pump from that tank to the shower. Some additional plumbing and valves required but nothing too complicated.
The pump and valves I have fitted for the shower in the back of the tug allow for many options with a couple of t way valves and a couple of connectors. All I use is the standard garden hose push on connectors. I just ensure I never boil the water in the tank. Just get it warm enough for a relaxing shower.

The other option may be to use the vehicle and a heat exchanger.
heat the water while charging the battery.
Use the same tank as mentioned above and just plumb from the van to the tug via a couple of hoses and connectors.

Just another option.

I will keep an eye on here for the finished product.

regards

Geoff

Thanks Geoff,

Sounds like you've given the hot water issue a lot of thought.

I have a mate who bought a cheap (non approved) instantaneous gas heater which he hangs on a tree with a gas bottle hooked up and a pump in the creek! I have been instructed to take the luxury route.

The advice seems to be that the Rinnai is too fussy about water pressure and gobbles a lot of gas when it's running. It weighs 15kg dry. The Truma weighs 7kg dry and 17kg full, so I think I'll go with that with a 240 volt option so I can heat heat from the generator if we're getting low on LP gas. There's always a solar option with more complexity and more weight.

This camper is taking forever to build and I want to keep things as simple as possible and practical for use with any tow vehicle.

I have a very clever CAD guy who is helping me so that we can get all of the composite panels pre-machined to that the the body clips together before all the joints are expoxied. So every detail has to be right before we order the panels. It's a real headache.

The chassis is almost ready for the galvaniser. We have a big beam axle with Landcruiser disks and stub axles, so that a busted axle can be replaced on the side of the road. The suspension is dual 100 Series trailing arms both sides on Nolathane bushes, with nine inch airbags, dual shocks each side and a panhard rod.

It's a big project and I'm having the time of my life!