how accurate is a flow cup ?

[johnnyplumb]

flow cups maybe convenient but are they accurate. can you read of say 9.8l or 11.5l and know for sure it is exactly 9.8l or 11.5l.

 

[Mike Jackson]

They'll never be that accurate but as far as I'm concerned they're near enough. If you want more accuracy time the time it takes to fill a litre jug and calculate it.

 

[WHPES]

They are accurate enough for most cases.

To be more accurate you need to fill a container using a stopwatch then measure out (kitchen scales are easiest - 1,000ml of water is very close to 1kg. (exactly 1kg at sea level I think if I can remember correctly from my O level days)

 

[johnnyplumb]

exactly, thats my take on it, flow cups are sold mainly for their convenience not their accuracy. if you want more accuracy get a bucket & stopwatch. sometimes the old ways are still the best ways.

 

[CES]

I think they are accurate enough for what we use them for. I only need to measure to the nearest half unit as an indication, if accuracy is needed then calculation is required.

 

[johnnyplumb]

what's the betting the flow cup/weir gauge was invented by someone called weir, who's made a fortune out of something that does'nt work. The guy that invented the bucket & stopwatch that's more accurate, has made hee haw. It's an unfair world.

 

[GQuigley67]

why doesnt someone put it to the test then and do both tests and compare results ?

 

[gasmarc]

you could always time the water meter if you want to be exact

 

[GQuigley67]

something we dont have round my way

 

[gasmarc]

There all over the place in london and very handy to turn the water off quickly