why do homes need water header tanks?

[bengasman]

You are asked to install a hot and cold water system in a property.
It's a new build with 4 showers , two bathrooms , utility room and kitchen. There is ample head height.
With no hope of upgrading the mains supply.
The flowrate is 14/lmin.

What system do you propose?
Or do you walk away?

Would it help if I repeated the answer 3 times in one post? 5? 11?

A mains system with the same size pipes will provide more litres per minute

Rubbish.

More pressure = higher speed.
Higher speed = more litres per minute through same passage.
How long have you been a plumber? Never looked at the results of what you installed?

Have you ever installed a h&c water system in a large property?

What part of: "I don't install open vent rubbish don't you understand?"
Therefore I don't do "h&c systems".
Presumably you mean "high use" property, and yes, I have designed and installed high use water supply.

And can you point to the legislation in the building regulations that state 14l/min supply to a large property is illegal?

There is obviously no reg that literally says 14l/min is illegal.
It is in the results/consequences that will occur where you breech the regs.
You can debate the definition of terms like "adequate", but even without accounting for tanks and cisterns, garden supply or diversity factor, 4 baths plus 2 showers plus 1 kitchen brings the flow to 2 litres per minute max.
That is NOT adequate by anyone's standards, at least not in England.
It would also create so much flow at lower levels, that the top level would experience reverse flow, (not adequate) and failure of taps. (not adequate either.)

If you can't see that, I am really wasting my time trying to explain the basics. What kind of jobs does your boss send you out on? Changing ball valves?
You are either not actually a plumber, or if you are, you must be working for the council.

 

[Norcon]

I have designed and installed high use water supply

Then you should know the answer to the following question........


You are asked to install a hot and cold water system in a property.
It's a new build with 4 showers , two bathrooms , utility room and kitchen. There is ample head height.
With no hope of upgrading the mains supply.
The flowrate is 14/lmin.

What system do you propose?
Or don't you know?

There is obviously no reg that literally says 14l/min is illegal.

Why bang on about it being illegal then or did you dream it up?

It is in the results/consequences that will occur where you breech the regs.

What regulations are being breached with 14/l min supply to a large property?

More pressure = higher speed.
Higher speed = more litres per minute through same passage

That's very funny because my mains pressure is 4 bar and delivers 16/l min to my kitchen tap and yet my gravity bath has about 2m head and delivers 20/l min.(and thats just the hot side delivery)
Obviously different passages but you get my drift.
Now try and answer the above question without resorting to your rear passage.

 

[bengasman]

....I have done that. An advantage is that an open vented system is less susceptible to back-siphonage. A type AF air gap is suitable for protection with fluid category 4. The usual domestic back-flow prevention devices are only suitable for use with fluid categories 3 (verifiable double check valve). I trust that you have a copy of the Water Regulations Guide?

There you have it, a real advantage. Other real advantages are that open vented systems are cheaper, have fewer mechanical safety devices and have less maintenance requirements.

The air gap might be less susceptible to siphonage, if you didn't have the tank in the first place, you wouldn't have antisiphonage measures on the tank. That is supplying a solution that is only needed because you created a problem.




Mine's a pint. [/quote]

Your argument is only a solution for the problem created by the tank itself, that does not provide an advantage of having a tank.

I anticipate you'll trying to squirm out of it. It seems your high opinion of your own expertise doesn't measure up to your expectations.

That is a selffulfilling prophecy.
Q "why are you in denial about being gay?"
A "But I am not gay"

A vented system is by definition open to bacteria, water may be crystal clear, it could be lethal, just the same as "clean" air could be toxic as hell.

Yes. But so is the mains supply, as I have detailed above. The overflow and air vent are screned and filtered and the only route for contamination is through some airborne pathogen. I don't know of that having happened. Maybe you know better.

In itself correct, but one essential difference.
Tank has, or can have, stagnant water reaching high temperatures in summer. Contrary to mains water, it does not (any longer) contain chlorine in sufficient quantities to kill or at least prohibit the growth of bacteria.

Many mains-fed systems (combis and unvented storage) are incapable of supplying an adequate flow rate to a bath.

Because the pipes are undersized.

No, the mains supply is inadequate to cope with the instantaneous demand. [/quote]
That is a chicken and egg argument. You can just as easily say that rather than storing water, you should increase the supply. It may be cheaper or more convenient in some cases, that does not make it a BETTER option than mains water.

I did exclude the price element from the equation as I am looking at the technical aspect. If you want cheap, walk to the lakeside or riverside in central Africa, and build a hut. Totally free hot and cold water for the rest of your life.

Irrespective of the size, a tank can run out of water if the outflow is larger than the fill speed, which makes it more fallible than mains.

 

[sooey]

I know that it is an unvented cylinder because:

1. It has the safety valves and all the explosion warnings on it.
2. There is an expansion vessel for it.
3. An unvented cylinder was considered the best option because he has a jacuzzi and two showers.
4. It is written on the cylinder.

I found out about this cold water tank when they were getting there loft converted into a room; they did not remove it and a cupboard was built to house it in.

Well it's obviously supplying some cold taps somewhere, maybe they have an over the rim bidet or some such. Now butt out while bengasman is making a cnt of himself.

 

[bengasman]

I have designed and installed high use water supply

Then you should know the answer to the following question........


You are asked to install a hot and cold water system in a property.
It's a new build with 4 showers , two bathrooms , utility room and kitchen. There is ample head height.
With no hope of upgrading the mains supply.
The flowrate is 14/lmin.

What system do you propose?
Or don't you know?

I do NOT engage in botch repairs; if there is a problem, I either bring the failing parts up to spec, or they can find somebody else who is willing to come up with some spittle and bailing wire solution because the client is too tightfisted to do it properly.

In very simple English:
"If you want me to work here Mr. Punter, you will have to bring the basis up to spec."
"Either that, or hire somebody else."

As for your question about the legality:
There is no law that says: Ben can not knock on his neighbour's door on wednesday morning, wait til he answers, and then punch his lights out.

Do you think that makes it legal to do so?

I described in very clear, very simple terms why 14l/min is no good.
I really can not be bothered to look up the relevant paragraphs in the regs, so let the subject of legality rest, as I am more than sure you can not show that it IS legal.
Let's keep it simple, if a normal kitchen tap (which produces less than a bath tap) produces between 10 and 15 litres a minute, how on earth do you expect to service between 7 and 12 points from 14 l/min?

You just don't have the foggiest what I am on about, and before I am wasting anymore time, please confirm that you have relevant training or experience.

 

[bengasman]

Now butt out while bengasman is making a cnt of himself.

Your spelling scks.

 

[Norcon]

If you want me to work here Mr. Punter, you will have to bring the basis up to spec."
"Either that, or hire somebody else."

Fair enough you are unable to offer a solution.
As Alan Sugar would say....
You're fired.

Let's keep it simple, if a normal kitchen tap (which produces less than a bath tap) produces between 10 and 15 litres a minute, how on earth do you expect to service between 7 and 12 points from 14 l/min?

Yes lets keep it simple so you understand.
Its called a GRAVITY system conforming to BS6700.

 

[bengasman]

Btw, I know you will be disappointed, but I will soon need to attend the typical weekend heating problem.
My beer is getting warm.

I will be back later, but unsure if typing legible text is still possible by then.
It might be tomorrow.

And don't get your hopes up about anyone actually being able to hold up the argument. I am tght as a camel's cnt in a snd strm, and if I am willing to bet a pint, you can rest assured I am pretty sure it is safe.
Now work out how safe I feel when I offer a night's worth of "drink til you drop"

Remember the parameters:

It has to be
technically better,
cheaper or more convenient do not count as arguments,
it applies to England only,
under legal circumstances,
which excludes situations where a tank is used because third party does not fulfill obligations

And I do pay my bills, so if I loose (perish the thought) I will fork out for the booze.
As I already mentioned I am a tightarrse, that will be in a normal pub, not stringfellows.

 

[mickyg]

if I've had to install a break tank and pump to overcome p1ss poor supply pressure(irrespective of the bore of supply pipe), that counts as stored water right? I fancy a night out

 

[bengasman]

If you want me to work here Mr. Punter, you will have to bring the basis up to spec."
"Either that, or hire somebody else."

Fair enough you are unable to offer a solution.
As Alan Sugar would say....
You're fired.

So far the best effort to logic, as he is a decidedly slippery character, and a good example of someone who I would suspect or trying to find someone who he could cajole into a situation that would shroud his own shortcomings.

It is essentially the same as installing a boiler on an old undesized gaspipe; you can install the boiler fully to spec without the slightest slip, it will never perform as it should, be illegal, and you are the one to blame.

Plenty of people are hungry enough to fall for it, I am not one of them.
I do it by the book, or I don't do it period.
Doing the job when you know (or should know) that the best you can hope for is a working patch up, is a road that leads to pain.
Your reputation will only be for cheap work, not quality.
The clients you get from that will only be those that are interested in price and your margins will always be minimal.
thanks, but no thanks. If I get that desperate, I will become a copper.

 

[bengasman]

if I've had to install a break tank and pump to overcome p**s poor supply pressure(irrespective of the bore of supply pipe), that counts as stored water right? I fancy a night out

It has to be

technically better
not a solution for 3rd party failure.

3rd party is bound to supply at 1 bar.

I am not a good enough lawyer to be able to point out where exactly the proof is that it also includes a certain volume, but I think swallowing the nonsense of "static pressure only" is a bit of a joke.
That would mean that as soon as the cistern starts filling at a rate of 1l/min, the pressure is allowed to fall to nothing.
Then again, anything is possible under this government.

 

[bengasman]

It does bring up an interesting aspect:
Is a breaktank with booster pump the same as unvented cwst?
Tbh, no idea.
Are you allowed to feed the kitchen tap off it?
Do the leading brands allow it to feed a combi/unvented cylinder?

 

[Norcon]

It is essentially the same as installing a boiler on an old undesized gaspipe

It isn't.
The cost of upgrading the water main may be prohibitive and disruptive to a homeowner and and will not endanger life if not carried out.
If your attitude to customers is reciting regulations to enforce your inabilities and shortcomings as a designer then upon seeing your advert in the yellow pages or other advertising media I would turn the page and look further afield.

 

[bengasman]

That's very funny because my mains pressure is 4 bar and delivers 16/l min to my kitchen tap and yet my gravity bath has about 2m head and delivers 20/l min.(and thats just the hot side delivery)
Obviously different passages but you get my drift.
Now try and answer the above question without resorting to your rear passage.

Higher pressure gives more l/min
for same pipe size and similar length.

If your bath is 2 metres from source and has 22 or 28 mm, it will obviously have more production than a 15 mm pipe over 12 metres.

Never actually tried it out, so can not confirm from seeing it with my own eyes, but if you stick enough bends/elbows in your 22 mm pipe, and at the same time you keep increasing the pressure on 15mm pipe, there will come a point where the 15 mm pipe produces more water than the 22mm one.
And don't say that the 15 mm pipe will pop under higher pressure, I use heavy grade pipe, not the cheap stuff. It withstands more than the 30 bar test pump can deliver.[/i]

 

[mickyg]

if I've had to install a break tank and pump to overcome p**s poor supply pressure(irrespective of the bore of supply pipe), that counts as stored water right? I fancy a night out

It has to be

technically better
not a solution for 3rd party failure.

3rd party is bound to supply at 1 bar.

you said originally that the exisiting problem with supply just has to be legal which it was. about 1.3bar static if I remember right. Flow rate was shocking, can't remember now but floating around 10 l/min. 3 bathroom, wc and kitchen
seperate supply to kitchen tap straight off main via water filter