did I dream it?

[Zyroman]

hello everyone, I think I saw in a recent copy of MMM a picture of someone messing with the water tank in their van, what interested me was that they seemed to have a long solid tube with a plug at the bottom which acted as an overflow. this sat in the normal plug hole and then once the water reached a certain level it drained down the tube and out of the van. having just bought a Helio filling point because my Wife was whinging at having to hold the hose in the filling hole it looks like something that would work really well for me, at the moment I have to keep an eye on the control panel and then rush out and turn the tap of. I am sure my van doesn't have any kind of overflow built in but would love to hear from someone if it does.

[Guest Tracker]

I would be surprised if your van's water tank does not have an overflow?

 

What happens if you leave the tap running and ignore the terminally unreliable water level sensors - excess water should emerge somewhere when the tank is physically full - does it?

 

Many overflows activate well before the tank is full to capacity which often means you are filling up more often than you need to - but these can sometimes be rerouted to allow more water to remain in the tank?

 

Have you looked underneath near the tank for an open ended tube which would more than likely be an overflow? There may well possibly be another overflow for the hot water system but that would be close to where the boiler is located.

 

I'm not sure what you mean by plugging a tube in a plug hole? Do you mean a sink plug hole? If so I tend to doubt that water would get to the sink without the pump being on?

 

I have only ever filled any van by listening for the overflow to - err - overflow before turning the tap off!

 

[Usinmyknaus]

No you did not - but be careful what you wish for....

 

My van has the same tank and plug/overflow arrangement (Knaus Sport Ti) and yes, it works very well as an overflow when filling the fresh water tank through the external filler spout. I just listen for the water pouring out and I know to turn off the tap - if I'm standing very close my left foot gets wet so I receive visible, audible and tactile warning all in one!

 

The downside of the arrangement is that it sometimes works too well, when you don't want it to - like going up or down steep hills, when an astonishing amount of fresh water can be lost. The elegant solution is, a plastic, domestic, wet radiator valve cap which fits beautifully over the stand pipe to stop splashing or surging water from flowing down the tube when en-route but with a hole in the underside of the cap to allow air in and prevent the tank having a vacuum created when the internal pump draws water. When I refill the tank I find it easier to remove the radiator cap from the tube to allow water to flow in faster from the external filler neck and the air in the tank to be expelled through the overflow tube.

 

Since the addition of the little radiator cap the system has worked brilliantly for me.

 

 

Bob

[Zyroman]

thanks Bob, does the bottom of the pipe have a taper fit that goes into for want of a better description a small plug hole? the tank in my Burstner has a small plug that sits into this hole which facilitates draining the tank. we have only been away twice so far and we only part filled the tank the first time because of the aforementioned Wife issue. the second time, using the helio addaptor I filled the tank righ up, we did not see any water exiting through an overflow but some did come of a small hole in the cap of the tank. that is what leads me to believe my tank doesn't have an overflow.

[Brian Kirby]

But, surely the system you describe would need a little more than mere friction to hold the stand pipe in place when driving. Water surges around the tank all the time, under braking, acceleration, cornering, and road camber changes. It seems at least possible that over the course of a journey that surging would displace a push fit stand pipe, draining out all the water. I just wonder if the Knaus version may be a little more sophisticated that it appears at first sight?

[lennyhb]

That is the type of tank usually fitted in a caravan, our last caravan had one. Totally useless in a Motorhome as you can't travel with the tank more than 25% full any more than that & by the time you get to your destination there is only 25% left anyway.

 

I would have expected the filling point on your van to have an overflow built in, normally a 10mm pipe from the top of the tank connecting to the back of filler inlet moulding.

 

Just noticed Brian's post above, the pipe screws into the bottom of the tank and doubles up as a tank drain by unscrewing it. Well it did on the one in our caravan.

[Guest 1footinthegrave]

Why would you want an overflow, mine overflows from the fill point with either me or the missus holding the hose to fill it up, I know it's full then, after all it's not likely to go anywhere else is it ? :-S

[lennyhb]

Zyroman - 2011-04-11 1:41 PM

 

thanks Bob, does the bottom of the pipe have a taper fit that goes into for want of a better description a small plug hole? the tank in my Burstner has a small plug that sits into this hole which facilitates draining the tank. we have only been away twice so far and we only part filled the tank the first time because of the aforementioned Wife issue. the second time, using the helio addaptor I filled the tank righ up, we did not see any water exiting through an overflow but some did come of a small hole in the cap of the tank. that is what leads me to believe my tank doesn't have an overflow.

 

I would expect your van to have the same filler as my Hymer which has a 10mm overflow tube connecting to the filler inlet.

I assume you mean a Heos water filler there are two types one for use with tanks with an overflow & the blue version for tanks without an overflow.

 

However if you use the standard one it will block your overflow as it exits around the top of the filler neck.

 

An easier solution is to fit a male/male Hoselock type coupler into the connector on the end of you hose, this is a good fit in the inlet so the hose doesn't fall out but the overflow water can still run out it works for us.

[Zyroman]

Mmmm, well the last time I tried it (sorry, yes with the Helos addaptor ) the water came out of what I assumed to be a vent hole in the cap and then ran into the underfloor area, not a lot you understand. I did get the Helos that said it would allow air out of the tank while filling if you did not have an overflow as at that point I was not sure if I did or didn't, I am planning a night away at the weekend so I will maybe give it another go and try overfilling it. Yes Brian , you are right, it was hard to tell from the picture if the bottom of the tube was threaded and if not then it would be unlikely to stay in place when in transit.

[lennyhb]

Where is your water tank is it in a double floor or under a seat, if it is under a seat lift the base up and have a look the overfill pipe will be obvious.

 

I am certain you will have an overflow, I would do the sensible thing and throw that filler you brought in the bin or return it as "not fit for purpose"

[Usinmyknaus]

Zyroman - 2011-04-11 1:41 PM

 

thanks Bob, does the bottom of the pipe have a taper fit that goes into for want of a better description a small plug hole? the tank in my Burstner has a small plug that sits into this hole which facilitates draining the tank. we have only been away twice so far and we only part filled the tank the first time because of the aforementioned Wife issue. the second time, using the helio addaptor I filled the tank righ up, we did not see any water exiting through an overflow but some did come of a small hole in the cap of the tank. that is what leads me to believe my tank doesn't have an overflow.

 

The upright pipe screws into the drain hole in the bottom of the tank and has a sealing washer above the thread. The arrangement is both a drain point and an air vent. As water is poured in through the external filler, air escapes through the pipe and as water is drawn off the tank by the on board taps, air is drawn in to prevent a vacuum. The standard arrangement has two flaws. When screwed in too tightly, the pipe is a pain to undo as my hand slips on the wet plastic so trial and error has taught me the appropriate torque to balance between being able to undo the thing to drain the tank and being tight enough to not drip water from the tank when in use. The mega flaw was that normal movement en route would reduce the contents through splashing over the upright pipe but the killer was steep hils which could reduce the contents by more than 60%. Knaus presumably intalled this system because it is an inboard, fully frost protected tank and this arrangement is relatively simple (and cheap for them?) and I can only assume they never actually tried using it in a hilly area. My adding the radiator valve cap to provide a splash guard for the top of the stand pipe has completely transformed its performance by making it practical in everyday use.

 

Bob

[ips]

1footinthegrave - 2011-04-11 5:30 PM

 

Why would you want an overflow, mine overflows from the fill point with either me or the missus holding the hose to fill it up, I know it's full then, after all it's not likely to go anywhere else is it ? :-S

 

Agree entirely with mr "onefoot"

Ours also has no overflow it just comes out the filler, anyway you can hear it gurgling a bit when its nearly at the top so can turn hose off before getting soaked.

 

"onefoot" - maybe its a german van that there on about and therefore over engineered ;-)

[lennyhb]

ips - 2011-04-13 1:00 PM

 

"onefoot" - maybe its a german van that there on about and therefore over engineered ;-)

 

You don't need one on British vans as there is so much damp in them from water ingress you wouldn't notice if it overflowed. (lol) (lol)