Fresh water tank vent

[BigJohn]

Hi all, just getting to grips with the new Ocean and todays task was sterilise the water system and flush it out, so I dropped in a couple of sterilising tabs, filled up the tank, waited 20 mins and then flicked on the tap and started to run it through.

All was working fine until I heard a strange knocking sound coming from the back. I switched off the tap and went to investigate - the sound was coming from the tank area. I tried to remove the filler cap but had real trouble and then realised it was stuck on by suction so gave it a good pull and off it came - along with the whole side of the van popping back out into position - such was the vacuum created by running the tap! Looks like no damage done, but surely there should be a vent somewhere to let air back in to the tank as it empties?

What am I missing?

Thanks,

John

 

[The Tall Luthier]

The tank is vented, otherwise that small pump couldn’t do its job fighting a vacuum.
I took mine apart yesterday, as others will testify, it’ it takes some turning and fighting with.
I had no choice as I left the tap on with no water in the barrel, the pump airlocked and refused to do its job for a while. I won’t be doing that again

 

[ArunAlec]

The tank is vented, otherwise that small pump couldn’t do its job fighting a vacuum.
I took mine apart yesterday, as others will testify, it’ it takes some turning and fighting with.
I had no choice as I left the tap on with no water in the barrel, the pump airlocked and refused to do its job for a while. I won’t be doing that again

Any idea where the vent is located? I can’t find one! Thought it might be designed into the filler cap but can’t see anything obvious.

 

[WelshGas]

Any idea where the vent is located? I can’t find one! Thought it might be designed into the filler cap but can’t see anything obvious.

I think the cap is not airtight and hence used as the vent.

 

[Lambeth Cali]

Hi all, just getting to grips with the new Ocean and todays task was sterilise the water system and flush it out, so I dropped in a couple of sterilising tabs, filled up the tank, waited 20 mins and then flicked on the tap and started to run it through.

All was working fine until I heard a strange knocking sound coming from the back. I switched off the tap and went to investigate - the sound was coming from the tank area. I tried to remove the filler cap but had real trouble and then realised it was stuck on by suction so gave it a good pull and off it came - along with the whole side of the van popping back out into position - such was the vacuum created by running the tap! Looks like no damage done, but surely there should be a vent somewhere to let air back in to the tank as it empties?

What am I missing?

Thanks,

John

On the issue with the knocking, not the vacuum, I would guess the pump has come lose. It clicks in the corner of the tank. When I had mine replaced the rubbish VW garage hadn't bothered to do this, which means it just bobs around the tank hitting the sides.

 

[marchugo]

The fresh water tank is vented, see pic. It's a small white plastic pipe called Fresh water tank breather or overflow. It sits left from the filler neck.

Regards from Amsterdam,

Marc.

 

[BigJohn]

Thanks all. The knocking noise continued after I switched the tap off, I think it was caused by the vacuum straining something.

Thanks @marchugo, I'll take a look, maybe I was just draining it too quickly and the air couldn't get in fast enough - you wouldn't normally run the sink tap for so long, bit you might with the shower attachment.

 

[BigJohn]

I took a look and found the vent outlet thanks to Marc's diagram, it is just inside the filler neck but on the sealed side of the filler cap which has what looks like an airtight rubber seal on it. There is a curious little hole on the inside of the cap - very middle of the white plastic 'bung', but that doesn't appear to vent - at least not by the strength of my lungs!

 

[ArunAlec]

I took a look and found the vent outlet thanks to Marc's diagram, it is just inside the filler neck but on the sealed side of the filler cap which has what looks like an airtight rubber seal on it. There is a curious little hole on the inside of the cap - very middle of the white plastic 'bung', but that doesn't appear to vent - at least not by the strength of my lungs!

I had a go at blowing my cap this morning….same conclusion!

 

[Hawthorn37]

I’ve found that when cleaning / emptying the tank I have to remove the filling cap, or wait a couple of hours to let the tank drain through the valve. With the cap off, the tank empties in a couple of minutes, after a flush through the tap.

On a slightly different aspect, are we happy about using the (cleaned) tank for drinking water?. I see some other Cali owners filling up flexible drinking water containers.

 

[WelshGas]

I’ve found that when cleaning / emptying the tank I have to remove the filling cap, or wait a couple of hours to let the tank drain through the valve. With the cap off, the tank empties in a couple of minutes, after a flush through the tap.

On a slightly different aspect, are we happy about using the (cleaned) tank for drinking water?. I see some other Cali owners filling up flexible drinking water containers.

Personal choice. We use it and have done so for the last 7+ yrs. We’re still here.
Each fill up has Katodyne added.

 

[jeff]

Never put a cleaner in water tank 14 years on still drinking it and no problems.
always take cap off when emptying otherwise water doesn’t all drain away .

 

[Hawthorn37]

Personal choice. We use it and have done so for the last 7+ yrs. We’re still here.
Each fill up has Katodyne added.

You use the Katadyn purifying tablets - 1 tablet / litre?

 

[Sad]

Same here, drink the water from the tank and use Katadyn (but the liquid)

 

[WelshGas]

You use the Katadyn purifying tablets - 1 tablet / litre?

As @Sad . Liquid.

 

[WelshGas]

Never put a cleaner in water tank 14 years on still drinking it and no problems.
always take cap off when emptying otherwise water doesn’t all drain away .

What do you "Disagree " about.

 

[Lambeth Cali]

I’ve found that when cleaning / emptying the tank I have to remove the filling cap, or wait a couple of hours to let the tank drain through the valve. With the cap off, the tank empties in a couple of minutes, after a flush through the tap.

On a slightly different aspect, are we happy about using the (cleaned) tank for drinking water?. I see some other Cali owners filling up flexible drinking water containers.

I fill a water bottle when camping. Not because I dont want to drink van water but because if we are away for 2 weeks I dont want the van water to run out and also because we almost always cook outside and so having a water bottle to hand is usefull.

 

[Hawthorn37]

I fill a water bottle when camping. Not because I dont want to drink van water but because if we are away for 2 weeks I dont want the van water to run out and also because we almost always cook outside and so having a water bottle to hand is usefull.

Makes sense having water handy if you need outside the van. We travel with a water fill hose (hygienic blue type and assorted connections), then refill as needed, but it depends if you’re heading to a site with facilities or wild camping I guess. We’ve also concluded it’s a waste of fuel lugging around an extra 30 litres of weight, so we’ll be setting off with a minimal water fill, then top up on arrival.

 

[BigJohn]

Thanks all, sounds like ours is behaving normally, although seems a little odd that the vent isn't sufficient to run the tap continuously.

I'm not sure about using Katadyne regularly though - there is a WHO report on it, I shall read thoroughly.

 

[WelshGas]

Thanks all, sounds like ours is behaving normally, although seems a little odd that the vent isn't sufficient to run the tap continuously.

I'm not sure about using Katadyne regularly though - there is a WHO report on it, I shall read thoroughly.

The WHO report is about a ceramic filtration system marketed by the same company. Totally different.
The liquid I’m referring to is this.

Katadyn – Micropur Classic Water Purification (1,000 Litres) - CampervanBits

Micropur Classic inactivates bacteria in water tanks and containers. It is ecologically friendly and keeps water free from germs, algae and odours. Silver

vwcaliforniaclub.com

 

[BigJohn]

The WHO report is about a ceramic filtration system marketed by the same company. Totally different.
The liquid I’m referring to is this.

Katadyn – Micropur Classic Water Purification (1,000 Litres) - CampervanBits

Micropur Classic inactivates bacteria in water tanks and containers. It is ecologically friendly and keeps water free from germs, algae and odours. Silver

vwcaliforniaclub.com

Nope, it was one on silver purification I was looking at, but haven't read it properly yet - will report back.

 

[BigJohn]

Ok, I've had a read - not all of it, those guys really know how to write a report! The TLDR; is, no-one really knows how much silver is too much but the WHO give a guideline of 0.1mg/L (based on 70 years of consumption, this would be half of the estimated lifetime amount you can consume without any ill-effects!). German authorities quote 0.08mg/L and the USA 0.2mg/L. If I've worked out the dosing correctly, the Katadyn classic is 0.07mg/L and the Forte is 0.082mg/L, so they should both be fine for long term usage.

However, the report also states - "In drinking-water treatment applications, silver (ionic silver, experimental silver nanoparticle applications and silver-coated ceramic filters [ionic silver and silver nanoparticles]) has generally only shown to be effective against bacteria (i.e. 1.6 to 7.6 log10 reductions), most notably E. coli, with relatively long contact times. Based on the current available evidence, which is particularly limited for viruses and protozoa, silver does not appear to meet the WHO minimum performance recommendations for POU treatment products, which require effectiveness for two of the three pathogen classes"

And - "On the basis of the significant data and performance gaps in disinfection efficacy as a primary disinfectant of water, the limited data on the range of microorganisms against which it is effective and under what conditions, and the availability of widely used, well-characterized disinfectants, silver is not recommended for use as a primary disinfectant in drinking-water supplies at this time."

I'm no chemist, but reading between the lines, I think the silver prevents growth of bacteria but doesn't necessarily kill it - so it keeps your water clean in storage rather than actually cleaning it.

I note that the 'Forte' version of Katadyne has more conventional chlorine in it as well, which would do the cleaning, and the silver would keep it that way?

Full report here if anyone is struggling to sleep - https://www.who.int/water_sanitation_health/publications/silver-02032018.pdf

 

[Hawthorn37]

Ok, I've had a read - not all of it, those guys really know how to write a report! The TLDR; is, no-one really knows how much silver is too much but the WHO give a guideline of 0.1mg/L (based on 70 years of consumption, this would be half of the estimated lifetime amount you can consume without any ill-effects!). German authorities quote 0.08mg/L and the USA 0.2mg/L. If I've worked out the dosing correctly, the Katadyn classic is 0.07mg/L and the Forte is 0.082mg/L, so they should both be fine for long term usage.

However, the report also states - "In drinking-water treatment applications, silver (ionic silver, experimental silver nanoparticle applications and silver-coated ceramic filters [ionic silver and silver nanoparticles]) has generally only shown to be effective against bacteria (i.e. 1.6 to 7.6 log10 reductions), most notably E. coli, with relatively long contact times. Based on the current available evidence, which is particularly limited for viruses and protozoa, silver does not appear to meet the WHO minimum performance recommendations for POU treatment products, which require effectiveness for two of the three pathogen classes"

And - "On the basis of the significant data and performance gaps in disinfection efficacy as a primary disinfectant of water, the limited data on the range of microorganisms against which it is effective and under what conditions, and the availability of widely used, well-characterized disinfectants, silver is not recommended for use as a primary disinfectant in drinking-water supplies at this time."

I'm no chemist, but reading between the lines, I think the silver prevents growth of bacteria but doesn't necessarily kill it - so it keeps your water clean in storage rather than actually cleaning it.

I note that the 'Forte' version of Katadyne has more conventional chlorine in it as well, which would do the cleaning, and the silver would keep it that way?

Full report here if anyone is struggling to sleep - https://www.who.int/water_sanitation_health/publications/silver-02032018.pdf

Yes, I read it also, and (also as a non chemist) it says to me that ‘the jury’s out’ on the benefits, although I take the purpose of the report as being for municipal water treatment.

Personally, I have an aversion to consuming nano particles on a voluntary basis, so I think we will go down the route of a ‘good clean’ every few trips. I’m going to mirror the CIP (clean in place) routine used in food factories, breweries, etc. (used to be involved in design and build of these), but replacing industrial caustic / sterilant with Milton. I’ve tested a method that works for me, cleaning the fresh water tank, and the waste tank, but a warning - I don’t have any swab tests to prove sterility

1. Fill clean water tank, and flush through tap to waste tank (with water fill cap removed).
2. When waste tank is full, empty to drain, and drain the clean water tank.
3. Fill clean water tank again, at part full add 3 Milton tablets via the filling inlet. Milton instructions are 1 tablet per 5 litres water to make a full strength sterilising solution. I believe half strength will be good enough for this application, and less likely to leave any taint, or be too aggressive for any seals.
4. Flush through the tap and shower connection for a couple of minutes.
5. Allow 60 minutes contact time. Milton instructions are 15 minutes, so I think 60 minutes with a half strength solution will be good enough to get to any crevices without exposing any butyl seals too much. During this time, I took a short drive, many corners and roundabouts, to move water round a bit.
6. Empty clean water tank through sink tap into the waste tank filling it (outlet closed), and flush through shower connection.
7. When waste tank is full, allow waste tank to sit full for 30 minutes, and continue to empty the clean water tank via the drain.
8. Refill the clean water tank, flushing through tap (to waste tank) for a minute.
9. Drain clean water tank, and waste tank. Then close both drain valves.
10. Finally, refill the clean water tank, and do a sniff and taste test.

After doing this, there was no detectable taint.

 

[jjpoppy]

I took a look and found the vent outlet thanks to Marc's diagram, it is just inside the filler neck but on the sealed side of the filler cap which has what looks like an airtight rubber seal on it. There is a curious little hole on the inside of the cap - very middle of the white plastic 'bung', but that doesn't appear to vent - at least not by the strength of my lungs!

I've just drilled a 2mm hole in the centre of the 'bung' of my filler cap, and hey presto my tank now vents - I did this as the vent pipe feeds into the filler cap, so it needs to vent through the cap. I can now drain my tank without taking the cap off.