System boiler enough for my house?

[Agile]

he used the garden tap, he did the pressure test with one device and another test with a flow cup.

It does sound as if he was properly measuring the dynamic flow using a pressure gauge on one outlet and a flow cup on another!

Its good to hear of installers doing that measurement properly! So many don't even understand dynamic flow ! It would typically be quoted as 20 litres per minute @ 1 bar !

Tony

 

[indus]

What additional information do you get by measuring the garden tap WITH the kitchen cold tap on? Is this what is referred to as the dynamic as opposed to static flow rate?

If there is very little difference between the flow rates you know you have good pressure.

I suggest using the garden tap because many kitchen taps, particularly the cheaper ones will give false readings as they restrict the flow.

All flow is dynamic. Static flow is contradictory.

It's the pressure which is static (no flow) or dynamic (flow).

Thank You

 

[indus]

he used the garden tap, he did the pressure test with one device and another test with a flow cup.

It does sound as if he was properly measuring the dynamic flow using a pressure gauge on one outlet and a flow cup on another!

Its good to hear of installers doing that measurement properly! So many don't even understand dynamic flow ! It would typically be quoted as 20 litres per minute @ 1 bar !

Tony

Surely you mean dynamic pressure not dynamic flow? As DH pointed out flow always has to be dynamic, it's the pressure that can be static or dynamic

 

[Agile]

Both flow and pressure can be dynamic. Only pressure can be static.

However I prefer to use the term "dynamic flow" in this context to differentiate between "flow rate" measured and "dynamic flow rate" measured.

Most nupties measure the "open pipe" flow rate which is of limited use.

The useful measure is the "dynamic flow" which is the flow rate which can be taken whilst leaving a chosen pressure of say 1 bar in the pipework.

I like 1 bar because most showers work best with this pressure and its adequate to ensure the pressure loss through combi boilers and cylinders is not significant.

Tony

 

[doitall]

I think if the numpty opens a kitchin tap and measures 24Ltrs/min at peak and off peak times it's a very useful test Tony.

If you have sufficient volume the pressure is irrelevant to a degree.

 

[Agile]

All a measurement of 24 li/min at an open tap can indicate is that the dynamic flow rate MIGHT be adequate!

It could be powered by a dynamic pressure of only 0.5 bar but just giving a good flow from large diameter pipes and taps.

After going through a combi boiler there will be inadequate pressure to give that exhilarating tingly feeling of a nice shower on your naked body!

Or bodies if you are saving water by showering together!

Tony

 

[doitall]

Of course you could have a 50mm mdpe water supply for your 2 up 2 down but I think that is unlikely.

Average domestic will be 15-25mm, in which case there must be a reasonable pressure to get a flow rate of 24Ltrs/min.

 

[D_Hailsham]

Both flow and pressure can be dynamic. Only pressure can be static.

It's not a case of flow can be dynamic, it has to be dynamic. Flow can not be static.

OK , you can measure the flow rate at a specific pressure, but to then call this the "dynamic flow" is meaningless. Much better to say that the flow is X litre/min @ Y bar pressure.

 

[CBF]

OP if you get a water softner then a hard water supply must be connected to the boiler/heating system, you CANNOT feed a WB from the sofened side.

I was talking to a home owner recently who has got the idea that only softened water should be used in heating systems.

To add to the complications, they have had differing advice when calling the UK or German offices of the boiler maker!

It's not just WB it's any boiler with a ally hex, it's just that WB have their heads so far up their backsides that they can't see they should change to stainless

 

[Agile]

The home owner was considering a boiler with a stainless HE.

 

[CBF]

Tony, they have had two quotes for a WB

 

[D_Hailsham]

he used the garden tap, he did the pressure test with one device and another test with a flow cup.

If he measured the pressure while the water was flowing, that's good. He was measuring the dynamic pressure.

 

[doitall]

he used the garden tap, he did the pressure test with one device and another test with a flow cup.

If he measured the pressure while the water was flowing, that's good. He was measuring the dynamic pressure.

Yes Dave, and he/she should do it at peak and off-peak times, especially in London or low pressure areas