Mains water to house drop in pressure

[Harry Bloomfield]

Needle moved when turning on the garden tap but didn't move when any other taps went on. I have a 25mm mdpe supply pipe

Then, only some sort of restriction, between the garden tap, and the rest of your water supply could allow that.

Might your garden tap, be on a different supply pipe entirely?

Might there be a partly closed stop tap, only limiting the supply to all but the garden tap? Try closing your house stop tap, then see if the garden tap supply is stopped.

 

[Ab12]

Then, only some sort of restriction, between the garden tap, and the rest of your water supply could allow that.

Might your garden tap, be on a different supply pipe entirely?

Might there be a partly closed stop tap, only limiting the supply to all but the garden tap? Try closing your house stop tap, then see if the garden tap supply is stopped.

Setup is as so:

MDPE in 25mm to mains stopcock

That splits immediately to an isolator then runs to softener which runs to my bathrooms up and down, toilets, kitchen sink for hot, dishwasher, washing machine etc. (the softener is currently bypassed so not active- it is a HF softener however with 22mm pipes)

The other split from the MDPE in goes to my kitchen sink for hard water and nowhere else.

I have a feeling my outside tap tees off from the soft that goes to my dishwasher

I've checked all stopcocks and isolators and they are all fully open

 

[Harry Bloomfield]

I have a feeling my outside tap tees off from the soft that goes to my dishwasher

I've checked all stopcocks and isolators and they are all fully open

A photo of a quick pencil diagram might have been better/easier to follow, but it sounds as if the problem might be at your softener bypass. Double check it is fully open, if it is, take it out and make sure the washer is not breaking up, partially obstructing the flow, and that it allows full flow diameter.

 

[Ab12]

A photo of a quick pencil diagram might have been better/easier to follow, but it sounds as if the problem might be at your softener bypass. Double check it is fully open, if it is, take it out and make sure the washer is not breaking up, partially obstructing the flow, and that it allows full flow diameter.

Will take a look, it's this style bypass

 

[Dereekoo]

Bit confused how you take the pressure reading at your stopcock whilst water running to various taps, has it got a side stub or something to fix your pressure gauge to. Having said that; 3bar is well past minimum requirements for water supply pressure and if you are getting more than 10 litres/ minute flow that also passes minimum requirements and at that pressure you should easily get 10l/m unless there is a major constriction

 

[Ab12]

Then, only some sort of restriction, between the garden tap, and the rest of your water supply could allow that.

Might your garden tap, be on a different supply pipe entirely?

Might there be a partly closed stop tap, only limiting the supply to all but the garden tap? Try closing your house stop tap, then see if the garden tap supply is stopped.

A photo of a quick pencil diagram might have been better/easier to follow, but it sounds as if the problem might be at your softener bypass. Double check it is fully open, if it is, take it out and make sure the washer is not breaking up, partially obstructing the flow, and that it allows full flow diameter.

Diagram attached. The bypass seems to be okay (though may not be internally)

I have now got two garden taps (one soft and one hard as in drawing)

I attached the gauge to the hard garden tap which tees off immediately after the mains comes in, and then started turning on taps in the house, the needle only moved when the air spluttered through the system as it refilled with water, as soon as it was a normal flow through the taps the pressure needle rebalanced back to it's static number.

Perhaps the gauge is broken?

I'm not sure I'm understanding how the the softener bypass could cause the pressure gauge attached on to the hose pipe not to change after taps are turned on?

Should I attach gauge to washing machine and then start turning on taps (this would be measuring and testing after the bypass i.e. what is the soft water system usually)

 

[Dereekoo]

Now need discharge from kitchen tap when fully open so likely pressure drop along 25mm mdpe can be calculated but as stated 3 bar is good pressure. Similarly on garden tap.

 

[Johntheo5]

Possibility of non return valve in/at the tap where the PG is installed?
Just slacken the PG connection to allow a very slight water dribble/leakage, this will allow any NRV to open to allow a true PG reading.

 

[Ab12]

Possibility of non return valve in/at the tap where the PG is installed?
Just slacken the PG connection to allow a very slight water dribble/leakage, this will allow any NRV to open to allow a true PG reading.

Yes garden tap has a double check valve I believe!

 

[Johntheo5]

Yes garden tap has a double check valve I believe!

If so, then the PG will only show the max pressure (static) as the NRV wont release any pressure between it and the PG when the pressure (dynamic) reduces, just slacken the PG a touch to give a tiny leakage.