Elbow fittings & flow loss

[Spinny]

About a year ago we replaced our lead water pipe with a new 32mm MDPE connection. This resulted in the flow through our outside tap being good at 37 l/m - tap connected off the internal 22mm mains copper pipe using 15mm copper pipe.

 

Since then the piping to the tap was changed as a temporary measure to plastic with various connectors. It now has 5 right angle elbows on the temporary pipe run (see pic). When I measure the water flow it is now 27 l/m - a 27% flow reduction.

 

I therefore conclude that each elbow is reducing flow by about 2 l/m.

 

My plumber has already fitted one 90 degree press fit elbow on another pipe run and the flow there seems lower than other internal taps.

 

I presume I need to tell my plumber to stop using 90 elbows and to use only swept bends if I want to maximise flow ?

 

 

[dpmiller]

a plumber did that?

[JohnMo]

If that's the plumbers handiwork, find a new plumber.

[SimonD]

2 hours ago, Spinny said:

I presume I need to tell my plumber to stop using 90 elbows and to use only swept bends if I want to maximise flow ?

 

I've seen much worse. I recently completed an unvented installation where I tested one of the outside taps and had barely 10l/m and it was only 2m from the rising main. There was another outside tap more than twice the distance giving me nearly 30l/m. It seems some plumbers have lots of excess fittings they want to get rid of and waste time making repeated visits to the local plumbing merchants counter. It also seems to be a rare thing that plumbers properly considers pressure drop.

 

Really what you want to tell your plumber is to not use any fittings at all and plan the routes accordingly - use MLCP/copper with a bender or use cold forming bends with plastic push-fit as a priority.

 

Your other problem appears to be that you've got 15mm off the 32mm MDPE, which really should be upgraded too.

[Spinny]

It is actually a right bu***** muddle at the moment under my stairs.

(I have had a constant nightmare with plumbers that say they will quote but don't, say they will come but don't, pop in to do something temporary and then never come back, only seem interested in doing the fastest possible rush job using only what is on site/in the van, don't really seem to want to solve issues, and/or want to bill criminal charges.)

 

See photo. If anyone can offer any suggestions for how this should be sorted I would be very grateful.

(Sadly I have the electricity main, the gas main & meter, and the water main all coming into an understairs cupboard.)

 

On the left front you can see a 32mm MDPE water main at sub floor ground level, which has been connected to 22mm copper.

This runs around in a 90 degree arc out of picture to the left because it still connects to the out of use lead pipe with a stop tap there.

Left middle in the photo there is then a 15mm tee down into a blue valve (off) and connector to 16mm MLCP - this MLCP runs as a mains water feed to my kitchen sink location.

Next along another 15mm copper tee with blue valve (on) that feeds (1) the outside tap and (2) an MDPE pipe under the floor that runs down to the end of the garden 40m away.

The connection to the garden MDPE pipe was made temporarily just to test for leaks - comes vertically down in copper with a blue lever valve (off).

Then a bypass valve for a monarch water softener (never yet installed) - bypass valve badly needs moving to the left to make proper room to connect flexihoses to the water softener.

Out of the bypass valve into a 25mm MLCP to the cylinder location 5m away (where it connects to 22mm copper to feed the pressure reducing valve).

 

You can also see the mains cable front left, middle is the gas enters through the wall and feeds upward in  copper through the meter above and back down to join the yellow gas feed off to the boiler. (Meter man can't touch the gas feed pipe, plumber can't touch the meter etc)

 

Answer welcome for a beer should we ever meet and a donation to the forum.