[tlwcs]

Any physicists on here please?
350 wyvale tank with 3kw element in the bottom, correctly fitted and 16amp wired
Tank filled to 2 inches from the top and set for 8 hours heating
The top of the tank is imploding
I’ve drilled a little hole in the black filler cap, to complement the one in the vent cap (spring loaded one)
I even left the lid off the night and struggled to re fit it the next morning
The only thing  I can think is the waters getting too hot.  (Where’s Nathon?)
Any ideas please chaps
Tony

[Ched]

So if tap water is about 7degC in winter and you have 3Kw heater for 8 hrs then the 350litre tank should have reached about 65degC assuming zero losses.
What temp do you have the immersion heater thermostat set to?
When you heat water it expands so having the top of your tank implode seems weird.
How is your tank mounted? IS it bolted in frame or a strapped down tank?
It could be that the sides are bowing pulling down the top of the tank unless a frame is there to stop the sides bowing?

[tlwcs]

So if tap water is about 7degC in winter and you have 3Kw heater for 8 hrs then the 350litre tank should have reached about 65degC assuming zero losses.
What temp do you have the immersion heater thermostat set to?
When you heat water it expands so having the top of your tank implode seems weird.
How is your tank mounted? IS it bolted in frame or a strapped down tank?
It could be that the sides are bowing pulling down the top of the tank unless a frame is there to stop the sides bowing?

Thanks Ched.
Thermostat set to max
Tank not insulated, keeps windscreen clear.
Tank in a frame but only strapped in.
I left it off last night so it’s relaxed back a little

[Smudger]

Hmm.. good point ched - interesting g problem

Darran

[Pete Thompson]

It’s not imploding exactly.

The heated water is making the tank plastic softer and then the weight of the water is constantly pushing on the sides, making them bow outward. (Imagine if you put water into a plastic bag, then placed it on a flat surface. It will tend to spread out flat).

This distortion has the effect of pulling the top of the tank inwards.

I have noticed the same very slight effect on my tank, but as it has a steel frame surrounding it, it’s just a very slight bulge in the lowest 3rd.

[NWH]

As the water vapour cools it condenses into liquid water,this lowers the internal pressure and can cause it to collapse and it’s one reason I wouldn’t go down this route.

[NWH]

Again speak to a plumber I haven’t seen many fitting plastic tanks in airing cupboards lately.

[NWH]

It’s not imploding exactly.

The heated water is making the tank plastic softer and then the weight of the water is constantly pushing on the sides, making them bow outward. (Imagine if you put water into a plastic bag, then placed it on a flat surface. It will tend to spread out flat).

This distortion has the effect of pulling the top of the tank inwards.

I have noticed the same very slight effect on my tank, but as it has a steel frame surrounding it, it’s just a very slight bulge in the lowest 3rd.

It’s not imploding completely but it’s on its way to doing so.

[Ched]

Just so you know Wydale tanks are made of Medium density polyethylene. Medium and high-density polyethylene has a melting point is typically in the range 120 to 130 °C.
So while a immersion heater wont get the pure upto anywhere near 120degC it may cause the tank to go a bit soft, certainly soft close to element if no circulation.

[G Griffin]

As the water vapour cools it condenses into liquid water,this lowers the internal pressure and can cause it to collapse and it’s one reason I wouldn’t go down this route.

Would lower pressure cause it to collapse?

[KS Cleaning]

Again speak to a plumber I haven’t seen many fitting plastic tanks in airing cupboards lately.

Alternatively, just login to CIU and ask the resident expert on all things hot, NWH 🤣🤣🤣🤣

[NWH]

🤣🤣😘

[Pete Thompson]

As the water vapour cools it condenses into liquid water,this lowers the internal pressure and can cause it to collapse and it’s one reason I wouldn’t go down this route.

How would that be possible when he’s drilled a hole in the lid? The “internal pressure” would equalise to the external pressure.

[NWH]

When he’s heating the water he is creating steam which turns into water vapour eventually if the blow off valve or hole in the lid isn’t big enough “boom”,how big is the air hole.

[NWH]

You would be better off putting 2 vents in either end of the tank you could use a threading tool for 2 female John Guest fittings,I’d use 3/8” or in English 1/2” and stick 6” long pipe in both.

[AuRavelling79]

I use an immersion and personally I think 50 degrees c is as high as I would go in the tank. If you want hotter then go diesel.

[֍Winp®oClean֍]

As the water vapour cools it condenses into liquid water,this lowers the internal pressure and can cause it to collapse and it’s one reason I wouldn’t go down this route.

Utter nonsense, the tank is vented you berk!🤔😆

[Smudger]

When he’s heating the water he is creating steam which turns into water vapour eventually if the blow off valve or hole in the lid isn’t big enough “boom”,how big is the air hole.

Steam ? - he's not boiling a kettle - if he was that would put your all singing a dancing system to shame wouldn't it.....

Darran

[NWH]

When that water is heating up in the tank it’s causing vapour or condensation if it’s not it would be a completely open lid even then there would be some steam after time,people are heating these tanks and insulating them during that process not only static in vans as well all that heat and steam will create pressure if you have a tiny little hole in the tank,matter of time before the tank folds in on itself.

[G Griffin]

When that water is heating up in the tank it’s causing vapour or condensation if it’s not it would be a completely open lid even then there would be some steam after time,people are heating these tanks and insulating them during that process not only static in vans as well all that heat and steam will create pressure if you have a tiny little hole in the tank,matter of time before the tank folds in on itself.

The tank isn't insulated.
Steam would create outward pressure and blow, as you said, but is it getting hot enough to create steam? I know Nathan did  get a bit of steam but it didn't blow. Then again, we haven't heard from him for a while  .
Steam could cause outward pressure, the tank could expand and then contract as it cools and that could cause it to sag.
I think it would be depend on the water temperature and composition of the tank.

I've just re-read the first line the thread, so ignore all that ^^^  .

[NWH]

Insulated or not if the steam can’t escape you’ll get pressure and Nathan had such an explosion he ended up in Scotland 🤣🤣, I’ve had pressure in my tank when it’s sat for ages recirculating back to tank if I’ve been dodging the rain for a while.
I have a large air hole but the 6” lid still hissed a bit on release.

[G Griffin]

Insulated or not if the steam can’t escape you’ll get pressure and Nathan had such an explosion he ended up in Scotland 🤣🤣,  ;

Joke of the year. So far  .

[NWH]

If you heater element a static tank and transfer it to van if you don’t have a big enough air hole you’ll still get a build up of pressure,that bloke that has the tank buckling I’d get a new tank in there and drill some decent sized air holes before you end up in the highlands with Nathan 🤣🤣🤣

[֍Winp®oClean֍]

Nigel, you're talking complete nonsense!
The tank is vented, if it wasn't you couldn't fill it with water. Water enters and air escapes, you replace air with water- basic physics. Where do you get the idea that condensation can create pressure? For one thing, once the tank is filled, there would be very little surface area available to condense on. For another, all that could possibly condense has had to originate from the same source to begin with. If the source of the pressure was internal then the tank could only expand, it wouldn't contract surely. To contract the pressure would have to be applied externally. To contract internally, you would have to create vacuum at a greater rate than the vent can counter balance at- and nothing we are discussing here is going to do that.
My guess is the sides of the tank are expanding with the heat thus pulling the top downwards- or the top of the tank is weaker than normal and just sinks with the heat.

[Dave Willis]

It’s true. Sometimes my 650l tank goes down to the size of a crisp packet by the end of the day. I just pop in an alkaseltzer and it pumps itself back up.

[NWH]

You put 50 odd degree water in a tank and put the lid on with a japs eye vent you’ll get a build up of pressure coz the hot water will produce steam.

[֍Winp®oClean֍]

You put 50 odd degree water in a tank and put the lid on with a japs eye vent you’ll get a build up of pressure coz the hot water will produce steam.

If that was true then the tank top would expand, not contract! I'm assuming you know the difference?

[NWH]

Yeah it may expand in a part of the tank too as mentioned on this thread he said it had swollen out on a section.

[֍Winp®oClean֍]

Yeah it may expand in a part of the tank too as mentioned on this thread he said it had swollen out on a section.

That's the opposite to what you have earlier implied.  Earlier you said condensing water vapour would lower the internal pressure of the tank, thus creating the crushing/imploding. In fact, you were so convinced by this, it was a particular reason for you not to use this system. You're either imploding or exploding, contracting or expanding.  Which one?  If the sides of the tank expand, this is due to heat softening the tank walls then the weight of the water inside, not pressure created by 'steam' with a tank of water gently and gradually heated, in a 'vented' tank to 65 degrees at best.

[NWH]

Mod note: Post removed.

[Smudger]

Yea I did say that you scrutinise my posts I reckon you’d like to expand my bottom tank and split me.

come on Nigel be the better man admit you talked a load of old billy bull

Darran

[NWH]

Speak to Neil at plastic water tanks about venting a tank or come to that installing a proper tank in a vehicle,come to that yet again ask his opinion on anyone who installs a wyvale type tank in a van lol he like to swear does Neil.

[֍Winp®oClean֍]

Speak to Neil at plastic water tanks about venting a tank or come to that installing a proper tank in a vehicle,come to that yet again ask his opinion on anyone who installs a wyvale type tank in a van lol he like to swear does Neil.

Better still, ask Neil to come on here and confirm your statements. 👍

[dazmond]

Nigel its wydale not wyvale.......there is nothing wrong with wydale tanks at all.....I have a 500L upright in my van inside a PF frame......never had any problems....I dont get leaks from the lid either like some guys do!

[P @ F]

Can we get a picture of this tank ?

[NWH]

Nigel its wydale not wyvale.......there is nothing wrong with wydale tanks at all.....I have a 500L upright in my van inside a PF frame......never had any problems....I dont get leaks from the lid either like some guys do!

Wydale Wyvale either way you look at it Daz they are only good for a static,farmers love em they keep there water in em they stick one on the back of a quad and drive to the sheep to give them water 🤣,it’s the same as IBC tanks they have no baffles and whys that ? It’s because they are supposed to be static.

[֍Winp®oClean֍]

Nigel its wydale not wyvale.......there is nothing wrong with wydale tanks at all.....I have a 500L upright in my van inside a PF frame......never had any problems....I dont get leaks from the lid either like some guys do!

Wydale Wyvale either way you look at it Daz they are only good for a static,farmers love em they keep there water in em they stick one on the back of a quad and drive to the sheep to give them water 🤣,it’s the same as IBC tanks they have no baffles and whys that ? It’s because they are supposed to be static.

Wydale tanks are baffled you berk! Oh dear.🙄

[tlwcs]

Can we get a picture of this tank ?

I’ll put one up tomorrow.
I think its the way it’s strapped.
Changed the van 15 months ago, bought tank and cage/frame but then went to work. One of those jobs eh?
Thanks for everyone’s contribution, well nearly!

[NWH]

Nigel its wydale not wyvale.......there is nothing wrong with wydale tanks at all.....I have a 500L upright in my van inside a PF frame......never had any problems....I dont get leaks from the lid either like some guys do!

Wydale Wyvale either way you look at it Daz they are only good for a static,farmers love em they keep there water in em they stick one on the back of a quad and drive to the sheep to give them water 🤣,it’s the same as IBC tanks they have no baffles and whys that ? It’s because they are supposed to be static.

Wydale tanks are baffled you berk! Oh dear.🙄

There’s baffled and baffled you know like some women are for looking at you fool,that tells me everything I needed to know about you if you think that’s a suitable baffled tank 🤣🤣 I’ve had 1 the last time I felt like that I was just about to arrive in France 🇫🇷 lol.
All I can say is it’s a good job you don’t design tanks for fire engines.

[֍Winp®oClean֍]

Nigel its wydale not wyvale.......there is nothing wrong with wydale tanks at all.....I have a 500L upright in my van inside a PF frame......never had any problems....I dont get leaks from the lid either like some guys do!

Wydale Wyvale either way you look at it Daz they are only good for a static,farmers love em they keep there water in em they stick one on the back of a quad and drive to the sheep to give them water 🤣,it’s the same as IBC tanks they have no baffles and whys that ? It’s because they are supposed to be static.

Wydale tanks are baffled you berk! Oh dear.🙄

There’s baffled and baffled you know like some women are for looking at you fool,that tells me everything I needed to know about you if you think that’s a suitable baffled tank 🤣🤣 I’ve had 1 the last time I felt like that I was just about to arrive in France 🇫🇷 lol.
All I can say is it’s a good job you don’t design tanks for fire engines.

Oh dear, an expert in baffled tanks now too.🙄
Just watch your house doesn't implode when you wake up to condensation on the windows tomorrow morning!😆

[NWH]

Mod note: post removed.

[AuRavelling79]

Nigel. Stay off this thread as you have nothing useful to contribute.

[deeege]

Nigel. Stay off this thread forum as you have nothing useful to contribute.

Edited for you.

[NWH]

Post removed says it all who runs this show 🤣🤣

[P @ F]

I think it’s a mixture of both hot water and how it’s strapped in , although I haven’t seen it I’m guessing that the straps are going over the tank but not frame , the two top edges are being pulled in once the tank gets hot .

My same tank has done it’s own thing , half of the top has bowed in and half has bulged up !

[tlwcs]

That is bang on mate.
The straps are cris crossed across the top and ratcheted tight. When the waters hot and the tank goes a little pliable, it crushes down.
I will not heat the water so hot and if it continues I will change the set up.
Thanks to all those who contributed and to the mods on my request removing some comments

[֍Winp®oClean֍]

Just be careful you don't get any condensation on the inside of your van................. you may walk out the door to a van like a crushed crisp packet sat on the drive!!👍🤐

[tlwcs]

Just be careful you don't get any condensation on the inside of your van................. you may walk out the door to a van like a crushed crisp packet sat on the drive!!👍🤐

Lol