When to add water?

I've always puzzled on when you can safely refill the water system and be fairly sure it's not going to freeze and damage anything?

Looking at the BBC weather forecast it says we're due -1 on Sunday night and a fair few nights of 1, 2 and 3 degrees to the end of March, whilst the first few days of April are listed as 4 degrees min.

Now I know some vans have tank heaters and that, generally a van's water systems can withstand the odd few degrees of frost, unless prolonged, but when do you think it would be safe?

Usually Mid April here Andy, fill and flush first, son " up north" is still frosty above sea level .
Boaby

There is no hard and fast rule as we have been known to have frost in June occasionally !!!  

Normal advice is mid April , but keep an eye on the forecast for your area.

I remember being out in our Adria in early '09 when we were house hunting and there were very hard frosts for a couple of nights but nothing froze up.

It depends surely on circumstances, if in the van and using it like we have trought the winter, no problems with water freezing, if van stood on drive and not used , fill later in the year, we keep oil heaters on in our vans so haven`t a problem with freezing, yet, crossed fingers says she.

Whilst keeping the interior of the van slightly above freezing by using some form of heating will probably stop internal pipes, pumps and taps from freezing and damaging themselves, it can be expensive in electricity bills and heater purchase, when there's a no cost option of draining down. Not to mention that it's hardly environmentally friendly.

The other issue is that under van tanks and pipes don't get any benefit from the internal warmth and in really cold weather they can freeze hard, even though sometimes protected by the bodywork above. Insulation can delay freezing, but can't stop frost penetration over long periods of cold.

Leave it empty at all times when not in use. Fill it immediately before you set off, I always travel with ours full. Refill as required at site, drain when you come home....all risk eliminated and you never have stale water in the tank.
As to heating the interior, heat rises and will do nothing to prevent an underslung non heated tank from freezing even if the inside is toasty!

Travelling with a full tank has consequences.

Every litre of water weighs 1kg.

So with water on board you're increasing fuel consumption and reducing available payload and , say, 100 litres at 100kg isn't an inconsiderable amount.

67Kg in my case, and we are minimalists. My travel is full fresh water, empty grey, empty toilet cassette, full flushing tank.

Vehicle is weighed before each long trip, usually 3200Kg or near enough in the above condition with both of us in it, all clothes, maps, food, 6 x 2 ltr drinking water, some wine and beer.

Reason for full water is we never know where we're going to end up night stopping, might be an Aire, might be a UK pub stop

So, some maths......67Kg + 12Kg (drinking water) = 79Kg

79Kg as a percentage of the vehicle weight = 2.5%, hardly significant I feel, and certainly unlikely to affect fuel consumption!

It's all also low down so reduces the c of g height.

When I see some of the stuff that others carry and rarely use I stop worrying. Peek in any motorhome with a garage as an example!!  Our payload after what  I detailed above is still circa 300Kg, bearing in mind the 3200Kg figure is literally setting off on a 3week trip, 300Kg = 300 bottles of wine! Our current record is 37!!!

Ian , if heading to a site we always travel with empty tanks as I cant see the point of humphin'  all that water when I can fill on arrival . Modern cars come without spare wheels etc to save a few kgs as manufacturers  strive to keep emissions down so it just makes sense to keep the van as light as possible. If you are wild camping fair enough but to just carry the equivalent of an extra passenger for the sake of it , I just cant see the logic. Every little helps as they say.....

When setting off, we travel with 30ltrs of water, as recommended by MH manufacturer, enough for our use on arrival. We then top up as required, but take a container of our own water to drink as it is soft water.

Bottled water is our preference for drinking, especially when abroad. Payloads are getting less, this would have a bearing on how much you carry I guess. Each of us will be different for various reasons. If using an aire I would carry more.

IanH wrote:79Kg as a percentage of the vehicle weight = 2.5%, hardly significant I feel, and certainly unlikely to affect fuel consumption!

On the contrary - it's absolutely 100% certain to affect fuel consumption.

When you think about it, every journey you make involves climbing and descending hills, involves braking to a standstill and accelerating to cruising speed and making turns.

In each case you have 79kg of additional load, which means doing more work, and that means that the engine has to work harder and consume more fuel.

Now it's true that some of the fuel consumption is due to factors (for example friction losses) that are not directly proportional to load, so you are likely to find that, say, 2.5% extra load only results in perhaps 2% extra fuel consumption - but it most definitely will have an effect!

Warwick Duo 2.2 ltr 130Bhp
Every tankful recorded as was trip and total mileage
Driven mostly briskly, always 2Km below speed limit on motorways or dual carriageways          Correct gear for the speed limit, 3rd in a 30Mph, 4th in a 40 and so on.
Rarely below 2000rpm as a consequence of above and very rarely over 3000rpm
Over 16000 miles it did 27.6Mpg, as I say, very carefully recorded.
In a £30k+ vehicle I think that acceptable and in no way would the load have 2% effect on the fuel consumption.
As Peter says....each to his own!!!

IanH wrote:Warwick Duo 2.2 ltr 130Bhp
Every tankful recorded as was trip and total mileage
Driven mostly briskly, always 2Km below speed limit on motorways or dual carriageways          Correct gear for the speed limit, 3rd in a 30Mph, 4th in a 40 and so on.
Rarely below 2000rpm as a consequence of above and very rarely over 3000rpm
Over 16000 miles it did 27.6Mpg, as I say, very carefully recorded.
In a £30k+ vehicle I think that acceptable and in no way would the load have 2% effect on the fuel consumption.

Err... yes. But you're not saying that you measured these figures without the extra 79kg load, and then again with the 79kg load, are you? So the figures on their own say nothing about how much extra it's costing.

I suspect what you are really saying is that you don't actually know how much extra fuel is being used, but you don't care?

That's absolutely fine by me, but it's not the same as it having no effect on fuel consumption.

Back to the OP's question. 

As mentioned above, we always fill fresh for each trip, usually at home, and drain down afterward. We never leave water in the system at any time of the year.

Our van is in storage, so, this means we don't have to worry about frost or stale water, no matter how long we are between trips. I dread to think how many of the vans in the storage place have water in them that's been there since March!

I ran an Adria Compact for a couple of years. IIRC it had a 120 litre fresh water tank (under the dinette bench) and an 80 litre waste tank under the van. Little risk of the fresh freezing when we were in residence, but the waste could.

More importantly, with both those filled available payload would go from 500kg to 300kg add in an 80kg passenger and the 30kg I am above the allowance for driver and the actual payload you can use becomes 190kg, which isn't a lot at all.

Roopert wrote:

IanH wrote:Warwick Duo 2.2 ltr 130Bhp
Every tankful recorded as was trip and total mileage
Driven mostly briskly, always 2Km below speed limit on motorways or dual carriageways          Correct gear for the speed limit, 3rd in a 30Mph, 4th in a 40 and so on.
Rarely below 2000rpm as a consequence of above and very rarely over 3000rpm
Over 16000 miles it did 27.6Mpg, as I say, very carefully recorded.
In a £30k+ vehicle I think that acceptable and in no way would the load have 2% effect on the fuel consumption.

Err... yes. But you're not saying that you measured these figures without the extra 79kg load, and then again with the 79kg load, are you? So the figures on their own say nothing about how much extra it's costing.

I suspect what you are really saying is that you don't actually know how much extra fuel is being used, but you don't care?

That's absolutely fine by me, but it's not the same as it having no effect on fuel consumption.

Actually I do  know exactly what fuel IS being used and as I don't intend to change my regime the possible saving is irrelevant!
However, here are the maths using you hypothetical 2% increase.
5000miles per year at 27.6Mpg = 181.15gallons used
27.6Mpg x 102% (your figure) =28.15Mpg. 5000miles @28.15Mpg = 177.62gallons used
Extra fuel = 3.53 gallons = 15.7l @, say £1.20 /l =£18.85 per year
So, in a nutshell I don't care. Running a £38000 vehicle, this disappears into nowhere and I have the advantage that wherever I stop I'm ready for the stop.
Thanks for your points on this, but I feel we should forget this one now!!
Bw
IanH

Ianh
like yourself I always set off with a full tank I will even be filling my extra new tank I just fitted full as well when wild camping .if you only part fill a tank you now have the movement of the water in the tank when you brake corner so for a safer and better ride as any tanker driver would say is best full or empty  .as for the £18.85 extra cost if correct per year you don't end up making extra trips now to  get water so will save that cost and time .the wind drag will bring down your mpg with items on the roof ?bikes on the back more than the extra weight ever will