I'm installing an irrigation system for some trees planted a few months
ago, a three hour trip to water them every few days is getting a bit old.

Water supply is 25mm blue mdpe terminating in JG speedfit stop tap and
3/4" tap connector, I suppose the pressure is "highish" because when I
reduce it down to 1/2" tap connector it has a tendency to blow the
hozelock connector off a hose.

For the irrigation pipe, I've fitted a pressure reducer that can take
input of 1-10 bar and give output of 1 bar, inside the black screw cap
is just a spring.

https://www.claber.com/uk/cod/91040/Block-system-Rainjet/Pressure-reducer

But when connecting the PRV, I can't get any get flow out of it, with
tap wide open (impossible to stop the flow with my thumb) very likely
the input pressure is exceeding the 10 bar maximum, so the PRV is
shutting off? But I when I close the tap down to a trickle (easily
stopped with a finger) I still got no flow, below the 1bar minimum? No
amount of adjusting the tap would get flow through the PRV.

AFAIK 1 bar is 10m of head, any reasonable way to estimate the supply
pressure? With the tap fully open, at the 3/4" connector the full flow
spurts about 18" vertically, restricting the flow as much as is possible
by thumb the jet will reach about 4m vertical ... what ball-park
pressure have I got? I'm looking to get another PRV to fit ahead of the
Claber one but don't want it to be too much of a guessing game what spec
I need ...

On Tue, 7 Jul 2020 09:45:23 +0100, Andy Burns wrote:

But when connecting the PRV, I can't get any get flow out of it,

Lets start with the obvious, got the direction of flow right?

AFAIK 1 bar is 10m of head,

Yep.

any reasonable way to estimate the supply pressure?

I don't think so short of having a pipe rising up to the point where
the flow stops. Anything with a flow is going to drop the pressure
dependant on how much flow and the resistance to that flow there is.

Is this supply the normal water mains? I'd be surprised if that is
above 10 bar. There are hi/lo limits to supply pressures. Water
pressure guages are cheap in the sheds...

--
Cheers
Dave.

Dave Liquorice wrote:

Andy Burns wrote:

But when connecting the PRV, I can't get any get flow out of it

Lets start with the obvious, got the direction of flow right?

Yes, it has an arrow on the outlet :-)

any reasonable way to estimate the supply pressure?

I don't think so short of having a pipe rising up to the point where
the flow stops. Anything with a flow is going to drop the pressure
dependant on how much flow and the resistance to that flow there is.

Is this supply the normal water mains?

Yes.

I'd be surprised if that is above 10 bar.

Having had a look at pressure gauges, and other PRVs they do seem to
top-out at 10 or 11 bar, I'll buy a gauge.

On 07/07/2020 09:45, Andy Burns wrote:

AFAIK 1 bar is 10m of head, any reasonable way to estimate the supply
pressure?

With a pressure testing gauge! (you can get them that screw onto the tap
connector)



--
Cheers,

John.

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| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:

Andy Burns wrote:

any reasonable way to estimate the supply pressure?

With a pressure testing gauge!

Well yes, but I was wondering it if was possible to get a sketchy answer
from flow rate or how high a jet of water could be produced, trying to
avoid too many round trips ...

On 07/07/2020 11:53, Andy Burns wrote:
John Rumm wrote:

Andy Burns wrote:

any reasonable way to estimate the supply pressure?

With a pressure testing gauge!

Well yes, but I was wondering it if was possible to get a sketchy answer
from flow rate or how high a jet of water could be produced, trying to
avoid too many round trips ...

In principle a fountain cannot put water higher than the head from which
it is fed.

Unfortunately, there are any ways in which it can be way less than that.

What about an old tyre coupled up to the mains, and then use a tyre
pressure gauge on that...

--
€œA leader is best When people barely know he exists. Of a good leader,
who talks little,When his work is done, his aim fulfilled,They will say,
€œWe did this ourselves.€�

ۥ Lao Tzu, Tao Te Ching

On 07/07/2020 12:38, The Natural Philosopher wrote:
On 07/07/2020 11:53, Andy Burns wrote:
John Rumm wrote:

Andy Burns wrote:

any reasonable way to estimate the supply pressure?

With a pressure testing gauge!

Well yes, but I was wondering it if was possible to get a sketchy
answer from flow rate or how high a jet of water could be produced,
trying to avoid too many round trips ...

In principle a fountain cannot put water higher than the head from which
it is fed.

Unfortunately, there are any ways in which it can be way less than that.

What about an old tyre coupled up to the mains, and then use a tyre
pressure gauge on that...

If he really has 10 bar pressure (~150 psi), that would be well over the
design pressure of the tyre! (it would probably take it, but might get
messy if it went bang)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 07/07/2020 11:53, Andy Burns wrote:
John Rumm wrote:

Andy Burns wrote:

any reasonable way to estimate the supply pressure?

With a pressure testing gauge!

Well yes, but I was wondering it if was possible to get a sketchy answer
from flow rate or how high a jet of water could be produced, trying to
avoid too many round trips ...

The height would vary with the size of the "nozzle" e.g. an open hose
will not project water anywhere near as high as one fitted with a spray
of some kind.

ISTM more likely the PRV is defective - I have seen them fail "blocked"
before.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:

The height would vary with the size of the "nozzle" e.g. an open hose
will not project water anywhere near as high as one fitted with a spray
of some kind.

As I originally mentioned, this varies from 18" for the open 3/4"
connector to 4m for the smallest opening I can make with my thumb over it.

ISTM more likely the PRV is defective - I have seen them fail "blocked"
before.

I wondered about that, but other than unscrewing the black cap and
finding the spring within, nothing else looked accessible, I should have
brought it home to look at ...

On 07/07/2020 13:58, Andy Burns wrote:
John Rumm wrote:

The height would vary with the size of the "nozzle" e.g. an open hose
will not project water anywhere near as high as one fitted with a
spray of some kind.

As I originally mentioned, this varies from 18" for the open 3/4"
connector to 4m for the smallest opening I can make with my thumb over it.

If that corresponded to only 4m of actual pressure, then you ought to be
able to stop the flow from the tap quite easily with your thumb...

ISTM more likely the PRV is defective - I have seen them fail
"blocked" before.

I wondered about that, but other than unscrewing the black cap and
finding the spring within, nothing else looked accessible, I should have
brought it home to look at ...

Or try it on your supply and see if it behaves differently.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Chris Hogg wrote:

It's not got some sort of flow controller hidden in the fitting, has
it, along with the pressure reducer?

couldn't see one inside the cavity wit the spring, but didn't have any
suitable tools with me.

I have one somewhere, taken off
an inherited hosepipe. Damn nuisance. It's supposed to stop the flow
if it thinks that the flow is too high, i.e. that the hose has split
or the spray head has come off.

I've ordered a pressure gauge, was going to collect it and check this
evening, but didn't realise toolsatan are closing at 5pm these days.

On Tue, 7 Jul 2020 09:45:23 +0100, Andy Burns
wrote:

I'm installing an irrigation system for some trees planted a few months
ago, a three hour trip to water them every few days is getting a bit old.

Water supply is 25mm blue mdpe terminating in JG speedfit stop tap and
3/4" tap connector, I suppose the pressure is "highish" because when I
reduce it down to 1/2" tap connector it has a tendency to blow the
hozelock connector off a hose.

For the irrigation pipe, I've fitted a pressure reducer that can take
input of 1-10 bar and give output of 1 bar, inside the black screw cap
is just a spring.

https://www.claber.com/uk/cod/91040/Block-system-Rainjet/Pressure-reducer

But when connecting the PRV, I can't get any get flow out of it, with
tap wide open (impossible to stop the flow with my thumb) very likely
the input pressure is exceeding the 10 bar maximum, so the PRV is
shutting off? But I when I close the tap down to a trickle (easily
stopped with a finger) I still got no flow, below the 1bar minimum? No
amount of adjusting the tap would get flow through the PRV.

AFAIK 1 bar is 10m of head, any reasonable way to estimate the supply
pressure? With the tap fully open, at the 3/4" connector the full flow
spurts about 18" vertically, restricting the flow as much as is possible
by thumb the jet will reach about 4m vertical ... what ball-park
pressure have I got? I'm looking to get another PRV to fit ahead of the
Claber one but don't want it to be too much of a guessing game what spec
I need ...

Here are critical reviews on Amazon saying the valve gets stuck shut.
https://www.amazon.co.uk/product-rev...l&pageNumber=1

On Tue, 7 Jul 2020 13:58:28 +0100, Andy Burns wrote:

As I originally mentioned, this varies from 18" for the open 3/4"
connector to 4m for the smallest opening I can make with my thumb over it.

This doesn't *sound* like anywhere near 10 bar... I have ~7 bar, part in 3/4"
pipework.

That said, I think you just can't tell that way: Imagine a very high pressure,
connected to your nozzle by just a pinhole. No jet, just a dribble -- but the
pressure would build up over time, and burst pipes eventually. Connect without
the pinhole, and you have a firehose/pressure washer.


Thomas Prufer

Dave W wrote:

Andy Burns wrote:

https://www.claber.com/uk/cod/91040/Block-system-Rainjet/Pressure-reducer

But when connecting the PRV, I can't get any get flow out of it
I need ...

Here are critical reviews on Amazon saying the valve gets stuck shut.

Hmmm, thanks. Have checked pressure and it's 2.5 bar so well within
input range, I brought the PRV home, no accessible parts, can't blow or
suck through it, will try an exchange at B&Q.

Andy Burns wrote:

I brought the PRV home, no accessible parts, can't blow or suck through it

Put it on my garden tap, heard it gave a "click" and water started
flowing, here it's on 15mm pipe and 1/2" tap, there it was on 25mm pipe
and 3/4" tap, pressure on both is ~2.5 bar.

Having removed it again you can suck and blow through it now, seems that
the valve locking-up as per the amazon reviews is real.

Maybe it doesn't like having to feed 50m of empty pipe? Though actually
I did try it with nothing on the output after it had originally failed,
so why did it "reset" itself?