Poor pressure on a megaflo??

Status
Not open for further replies.
ChrisR said:
The flow you're getting is much the same a standard pump of a similar head might provide, with such a low pipework resistance (each side of a twin):
As one might expect. The source of any given pressure is irrelevant to the static pressure of the water downstream (although the pump has the unique advantage of being able to have a higher static pressure than that provided by the mains). 3.0 bar could be provided by mains (with or without an accumulator), a 3.0 bar head pump or a tank raised 30 metres (tall building I know).

Where high flow rates cause the dynamic pressure to drop severely due to high resistance (undersized pipe) from the mains, an accumulator, pump or gravity feed tank will mitigate this temporarily. Whereas the boost from an accumulator decays progressively, the boost from a pump (drawing from a low level feed tank) and the gravity feed tank will decay abruptly when the tank empties. So it's all a question of appropriate sizing, whether its an accumulator or feed tank.
 
We knew we were deailng with a salesman, now we know we're dealing with a poor one.

Without an accumulator, . . . , as you reach the max flow rate the working pressure falls off significantly.
This is a double concealed lie.
It pretends
1) that the working pressure doesn't fall off as you reach maximum flow, if you have an accumulator. Of course it does, any supply will do that. Some do it less than an accumulator system.
2) it forgets that the pressure and therefore flow from an accumulator system drops off as you use it.

Because the accumulator has such a large volume, showers etc, even three running simultaneously, will still be invigourating to say the least.
The "large volume" of the accumulator is one of its main drawbacks - it's a pretty inefficient way of storing water, as only about half the volume is usable. Assuming you need to store any water at all, that is.
The "invigourating" (sic) qualities of the showers are not due to their being sourced by an accumulator per se. Any low resistance supply will be exactly the same. But any other method of delivering the same pressure and flow doesn't collapse it as you use it like an accumulator does.

Even at 1.5bar, the working pressure is impressive
Only if you want to call 1.5 bar impressive. Many if not most "designer" showers are designed for around 3 bar and look very sad at 1.5.

So it doesn't boost pressure per se, just makes better use of what you have.
Yes it does that. But only "better" in one respect, flow, not pressure (as required by those showers). And at huge cost. There are other, arguably better, and certainly more popular methods of achieving the same, and improvements over that.
Try increasing the size of the mains supply. Whatever flow you want, and not a lot of storage space required.

Now we get the real nonsense. Presumably there's a QVC style set of varnished nails to go with it.
The comparison between pumps and accumulators is a good one, and one we regularly discuss with customers. Accumulators negate negative and positive pressure pumps, are completely silent in operation, store potable water, continue to work in a power cut, and do not wake everyone else up in the house. My company does not specify shower pumps .
Accumulators do not, slightly, in any sense, "negate" pumps.
Pump noise is not even noticed in many installations. I was at a FLAT two days ago which had a 3 bar ESP pump. The occupants didn't even KNOW they had a pump. There would have been nowhere to put an accumulator. In houses big enough to accommodate huge accumulators there's usually somewhere to put a pump(s) so that noise simply isn't an issue. The bath taps make more noticeable noise.

Any plumber who thinks pumps need "wake everyone else up in the house" is an ignorant one. Or a dishonest one.
Any plumbing company which doesn't offer pumps is a remarkably incomplete plumbing company. "Because of the potential call backs" - try learning how to install pumps properly. You must be very afraid of seeing your customers ? Why would that be I wonder.

Accumulators have been around a long time and can be suitable in some situations, but they're a one trick pony.

Anyone who promotes them as the best solution, and excludes the other options, is deluding his customers and probably himself. We can't put it down to ignorance, which leaves dishonesty, incompetence, or both.

Just the sort of tiresome hobby-horse jockey nobody wants.
 
simond said:
The accumulator is certainly boosting the flow rate - up to 4 or 5 times the incoming flow rate in the test.
I'm with you so far, because you seem to be just saying "yes", albeit with 20 extra words. However, after this point you lapse into talking about what an accumulator "will" do - I was specifically talking about what your accumulator does do.

The accumulator will also make the working pressure closer to the standing pressure in the delivery of the water to the tap, because of the volume available.
Is your 450 litre accumulator three-quarters filled with water (when fully charged)? And you saying that, the volume of air that has been compressed in the accumulator will deliver an initial flow rate of merely 3 bar? Whatever you are saying I'm still lost, because you don't write in specifics, instead using such phrases as "the delivery of water to the tap". What are the units and magnitude of "delivery" in this context?

Without an accumulator, at 18 litres per min, as you reach the max flow rate the working pressure falls off significantly. Because the accumulator has such a large volume, showers etc, even three running simultaneously, will still be invigourating to say the least.
That's a pity - I was hoping for an invigorating shower. :(

Even at 1.5bar, the working pressure is impressive for this reason.
1.5 bar mains is a bit of a dribble in my book.

The comparison between pumps and accumulators is a good one, and one we regularly discuss with customers.
I didn't make it, don't think it's a good one, and I don't want to hear about comparisons anyway.

Accumulators negate negative and positive pressure pumps, are completely silent in operation, store potable water, continue to work in a power cut, and do not wake everyone else up in the house. My company does not specify shower pumps because of the potential call backs.
How very uninteresting. Could you now get back onto your own accumulator, and the measurements you took, and how they are achieved, and at what cost of space?

Edit - I've just noticed ChrisR's extensive post, a lot of which I've unwittingly duplicated. Oops.
 
Chris R

Huffy puffy!

I am sorry but I cannot see your point. We have established that with an accumulator the available flow rate is way in excess of that needed. The limitation is the pipework or the appliance.

Therefore my customers do enjoy a higher working pressure because it is very difficult for them to reach the limit of the flow rate of the water source.


I am disappointed that you have seen fit to let this debate become personal and made some defamatory comments. I detect that you, along with a few others, have become quite aggressive because you wanted to be right in front of your peers.

I am only interested in genuine technical advances that deliver. If it isn't covered by my physics A level, I'm not convinced. I am satisfied that I have proved to the forum that this design delivers - but anyone left in any doubt can always request specs from the manufacturer.

We are just an installation specialist; all you guys arguing are in the same business, for the level of detail you want (and the amount of personal grief being directed at me) I suggest you request some technical data sheets. Maybe you'll get up to speed with where we were 3 years ago. Maybenot. :lol:
 
Most of those drawbacks of a standard accumulator do not apply to an "Agile Accumulator".

The Agile Accumulator ­® can be supplied in any size and for example the 300 li model stores 300 litres ALL of which can be delivered to the showers!

This is how it works, the single outlet at the bottom fills the tank when its first connected with the air being expelled from the top by an electropnumatic valve until its completely filled with water at the static mains pressure.

When water is used in the house and the flow causes the pressure to drop below 1.0 Bar the air compressor cuts in and pressurises the top of the tank to 1.3 bar and forces the stored water out to the showers until the tank is empty. It therefore delivers the whole tank capacity of 300 litres to the outlets. At that point the compressor is switched off and the tank refills ready for the next demand session.

Tony Glazier
 
Sorry Agile

That won't work. Back to the drawing board.

However, there is a product on the way which has some key differences but will.
 
simond said:
I am sorry but I cannot see your point
simond said:
Sorry Agile
You seem to be sorry about a great many things; or do you just use the word without the meaning?

You haven't said that you're sorry for ignoring all of my questions - presumably I've been summarily dismissed from your sphere of interest. :roll:
 
Simon,

It really has been educational, thanks for the advice etc...
I'd never considered the possibility of such a device before, and the figures you posted speak volumes.

I think the difficulty with this type of product is that (without wishing to sound rude) there are plenty of people who will just slate it because they don't understand it.

I like to think that for me that isn't the case.

I have 4bar at home and a flow rate of 30l/min from the bath taps combined (hot and cold) and the space (and luckily) money for a large vessel - I'd love to see a larger flow rate (for showers mainly) and increasing the main size isn't really an option, pumps and tanks aren't either.

I still maintain that they aren't for everyone, but in a situation where you have a good static pressure but poor flow they offer a good solution to pumps and tanks without the associated noise and electricity usage.


Cheers
-Dan
 
Simon
Being "right" about what an accumulator is, is second nature to anyone who has worked with electronics. It's the direct analogue of a Capacitor, one of the three basic components. They store charge (water) at voltage(pressure) and provide a high current (water flow) for a predictable time.
That was what I reckoned when I saw the Dualstream literature years ago, and my view is the same now.

The reason I have become what you perceive to be aggressive towards you, (not accumulators) is that you use deliberately sloppy technical language to not just describe, but promote the device in a biased way.
You always revert to a simple, limited statement, ignoring other factors. But the real world is full of other factors, and those who deal with all of them are good engineers. Those who need time to understand features of different approaches are excusable. You now dismiss however, those who (genuinely) don't understand.

You forget, or omit, to mention the disadvantages of one solution, which of course is "yours", then dismiss other solutions using ridiculous exaggerations. This is bad engineering but not just through ignorance, you seek to mislead. The motive of personal gain is blatant, it's dishonesty.

In my opinion you deserve to be defamed.
 
toasty said:
I'd love to see a larger flow rate (for showers mainly)
Your system needs to be analysed to determine what's achievable, and the optimum route. We live in hope, but from current experience, Simon won't be doing that for you. You need a good, unbiased engineer.
 
toasty said:
........... the figures you posted speak volumes.

Very droll :lol:

I think the difficulty with this type of product is that (without wishing to sound rude) there are plenty of people who will just slate it because they don't understand it.

Or perhaps because they DO understand it.

I like to think that for me that isn't the case.

It would be nice to think so.

I still maintain that they aren't for everyone, ..........

Just as well. If we all had these, the present water shortage would be as nothing compared with the potential if we did.

.............but in a situation where you have a good static pressure but poor flow they offer a good solution to pumps and tanks without the associated noise and electricity usage........:lol:

This implies pumps and tanks are the problem. Accumulators have one significant problem, the inefficient use of space.

You rarely get an advantage without some disadvantage, but to sell an accumulator to someone is more of a marketing exercise than an engineering one.
 

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Status
Not open for further replies.
Back
Top