W
Water Systems
simond said:Unfortunately, like all on site measurements the results are difficult to translate from one installation to another because of external influences.
For instance, I could fill my bath much quicker with the hot and cold taps running flat out, rather than just the hot or cold, because of pipework resistances. So a lukewarm bath would fill quicker at my house but not be representative of real use.
I do not have laboratory conditions in my house and offered to take the trouble of making real-life measurements because of the negative and doubting comments of some participants, and their barracking that I was not supplying figures.
If you want to extrapolate some real test data I suggest you contact GAH, in the same manner that you would ask Vaillant on the performance of their combi at 42 delta T rather than the quoted 35 delta T. Taking measurements at a customer installation would not necessarily be representative.
Simon, the example given was in your house. What is the charge pressure of your accumulator? How long to fill the 120 litre bath. That's all. I don't doubt your word at all. I'm sure the system delivers. I'm not into saying it doesn't work.
And talking of figures, much hyperbole has been made in this forum about the relative costs of accumulators from X and Y, I haven't seen much evidence in hard fiscal terms. Someone bought one abroad, but surely you can do better than this?
The Reliance accumulators can be bought at about £300 for 200 litres (100 effective storage), then add a double check valve, PRV, PRV and tundish. That's it. What else? The cost is £450 for the 400 litre unit the last time I looked. So, say approx £500 to 550 for the lot. Having a quality two pump set on your cold tank would be more than £500. Accumulator are a good thing and in some circumstance are the ideal solution for poor mains flow. However a pump set froma tank will operate on any main pressure and flow from a tank which is sized up properly, It can charge up overnight, and size the tank for a days supply of water.
The Reliance accumulators have replaceable diaphragms with on site ease of replacement. An installer who knows the basics can put one together no problem at all. He needs to know a few basic calcs to know the accumulator charge pressure to get the stored water volume. The less the charge pressure the more water stored, but a lower dynamic pressure overall. Most are not capable of this, they only go for packaged solutions.
The same with a heat bank (thermal store with a plate heat X). I educated a self employed installer on these and how to make your own. Now when he gets a job, he orders the parts (a direct cylinder with appropriate tappings) and spends an hour in his garage assembling it. He makes a lot of money doing it this way, forgetting unvented cylinders totally. The average guy will only buy a packaged unit and do whatever the company instructions and tech dept says.