Mega flow system losing water pressure

[Jmills]

Firsr time post apologies if it's been covered.

I had a mega flow system fitted 9 months ago and if I'm in the shower for example and flush the toilet the pressure drops.

Same if I'm running a bath and turn the kitchen tap on, the pressure drops quite a lot.

I had a total house renovation and my builder is scratching his head and saying it's just how it is.

But I know that it's not.


Any tips and suggestions would be appreciated.

 

[ShaunCorbs]

Easy what's your incoming cold water main pressure and flow readings ?

And hope the builder didn't fit the unvented cylinder

 

[Jmills]

Easy what's your incoming cold water main pressure and flow readings ?

And hope the builder didn't fit the unvented cylinder

Hi. No idea. How would I find that out?

Also the pressure is fine with just one tap running. Really good pressure.

 

[ShaunCorbs]

Hi. No idea. How would I find that out?

Also the pressure is fine with just one tap running. Really good pressure.

from the cold kitchen tap or outside tap how long does it take to fill a 1 or 2 l bottle (which ever you have handy)

as for pressure you would need to get a pressure gauge

http://www.NoLinkingToThis/p/monument-tools-mains-water-pressure-test-gauge/82412

attach to an outside tap
and measure the standing pressure (with no outlets open)
and dynamic pressure (with the kitchen tap open or one outlet open)

hope this makes sense

 

[Jmills]

from the cold kitchen tap or outside tap how long does it take to fill a 1 or 2 l bottle (which ever you have handy)

as for pressure you would need to get a pressure gauge

Monument Tools Mains Water Pressure Test Gauge

attach to an outside tap
and measure the standing pressure (with no outlets open)
and dynamic pressure (with the kitchen tap open or one outlet open)

hope this makes sense

12.5 seconds to fill a 2 litre bottle.

 

[ShaunCorbs]

theres your problem around 10lpm way way under what is needed for an unvented cylinder, spec is a min of 20lpm

can you double check that measurement by using an outside tap

 

[Jmills]

theres your problem around 10lpm way way under what is needed for an unvented cylinder, spec is a min of 20lpm

can you double check that measurement by using an outside tap

Previous was kitchen tap.

Outside tap = 8 seconds for 2 litres

 

[ShaunCorbs]

Previous was kitchen tap.

Outside tap = 8 seconds for 2 litres

thats better but still lower than needed for an unvented cylinder

outside tap come out at about 15 lpm

i would say incoming water main is your problem
do you know what size and material type is it ?

 

[Jmills]

thats better but still lower than needed for an unvented cylinder

outside tap come out at about 15 lpm

i would say incoming water main is your problem
do you know what size and material type is it ?

No idea sorry. I'll have to get all that looked at.

Someone else suggested an accumalator might solve it. Does that make sense?

 

[ShaunCorbs]

No idea sorry. I'll have to get all that looked at.

Someone else suggested an accumalator might solve it. Does that make sense?

depends it would solve the drop in pressure when more than one outlet is open (wouldnt increase it) its an ok idea need to know what the incoming water main pipe is tho

wheres your cylinder located?

 

[Jmills]

depends it would solve the drop in pressure when more than one outlet is open (wouldnt increase it) its an ok idea need to know what the incoming water main pipe is tho

wheres your cylinder located?

Cylinder is in converted loft space, in its own room. So technically the 2nd floor(top floor) of my house.

 

[ShaunCorbs]

bit of a long shot any chance of a few pics of the cylinder and pipework etc?

 

[Jmills]

thats better but still lower than needed for an unvented cylinder

outside tap come out at about 15 lpm

i would say incoming water main is your problem
do you know what size and material type is it ?

2omm poly.

 

[ShaunCorbs]

stop tap open all the way up both of them?

 

[Best]

Wouldn't surprise me if a least one small bore isolating valve is fitted on mains supply or outlets. I don't trust builders and their plumbers

 

[Jmills]

Wouldn't surprise me if a least one small bore isolating valve is fitted on mains supply or outlets. I don't trust builders and their plumbers

Plumber returned and he measured pressure and he's getting 21 lpm at the boiler. He's scratching his head as it should be more than enough pressure.

 

[ShaunCorbs]

Plumber returned and he measured pressure and he's getting 21 bar at the boiler. He's scratching his head as it should be more than enough pressure.

Guess you mean 21 lpm ? As 21 bar would blow the cylinder up

 

[Jmills]

Guess you mean 21 lpm ? As 21 bar would blow the cylinder up

Edited.

Any ideas?

 

[ShaunCorbs]

Edited.

Any ideas?

Do you know where he tested the flow from ?

 

[Jmills]

Do you know where he tested the flow from ?

Can't quite remember I think he said coming out of the system.

 

[Welder]

Builderitis...

Best measure output from three taps. Open three taps fully and measure how long each takes to fill 1 litre. That gives you the true system ability. Then see if you have your 20 lpm.

Also, what size is the incoming main and the pipe at the stop tap? 15mm or 22mm? Does it reduce down to go up to the loft?