I just had a british gas guy around to give me a quote for some work.
(Or more importantly tell me what he thinks since they're bound to be
He seems to think that in order to put in their Albion thermal stores,
you need to increase your water main to 25mm plastic.
Is this true?
No. It is the pressure and flow of the main pipe that matters. 25mm is
ideal, but not necessary, if pressure and flow is fine with a 15mm/1.2".
Did he take the mains pressure? Did he measure the flow? You can do the
flow yourself by timing the filling of a bucket.
Static pressure is rarely a problem in itself unless really low. Flow rate
is much more important. However, low static pressure may be a cause of low
To measure it, you need a pressure gauge. Alternatively, try to block off
the flow from a mains cold tap with your finger. If it is impossible to do
so without squirting water sideways, the static pressure is OK in itself.
That depends on what you have at the moment. Find the best mains tap in the
house. This always used to be the kitchen tap, but these often now have
restricted passageways that affect the result, making it look worse than it
is. Sometimes the garden tap is a better bet. Measure both and take the
Now, time how long it takes to fill a bucket when the tap is on full. Divide
the capacity of the bucket (in litres) and divide by the number of seconds
taken to fill it. Multiply by 60. This gives you your flow rate in litres
For a mains pressure stored energy system, I'd say:
< 10 lpm - absolutely no good for anything
10-20 lpm - v.poor
20-30 lpm - poor to marginal
30-40 lpm - OK
40+ - excellent
Should you get below around 30lpm, start thinking of upgrading your water
main. 25mm MDPE would be a reasonable good sized water connection for a
house. If you're rich, then consider doing if you are below 40lpm.
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