hot water flow

[brian c]

Hi all,
I have a gas boiler and a mains pressure cyclinder, the hot water feed to the kitchen is about 65 ft long it takes a long time for the hot water to flow through, the pipe is 15mm if i change the pipe to 10mm will it improve the time it takes for the hot water to flow? also will it effect the water flow much?.
any advise gratefully received.

 

[justlead1]

Hi Brian, It will effect the flow but might be acceptable. Why not connect the coil of 10 mm to the same supply{mains ) a see what comes out the end? If it ok rater than taking out all the 15 mm why not use it as a sleeve / duct? Good Luck

 

[Puddle]

The pressure will probably still be ok, hot water will not come through any quicker,it still has the same distance to travel, just less water volume will come through tap and less hot water will be wasted in pipe work when tap turned off, do not know what you’re hot water demands are in your kitchen, maybe another heat source could be used or a hot water circuit fitted

 

[Blackcatgas]

Fit a secondary return pipe with a bronze pump.

 

[Bernie2]

Hmm!

Reducing pipe size gives roughly the same flow if the pressure is the same, it just seems quicker. What happens is that the pressure drops and the velocity increases, the flow is hardly affected.

If you get a drum 10' high and put one 1/2" hole and one 1/8" hole in at the same level. The 1/8" hole water jet goes further than the 1/2" because the velocity is greater. Yet they are both at the same pressure.

It works a bit like a gate at a football match, the crowd all make for it and squash the few going through to make them go faster and so instead of 10 a breast going through the gate in an hour, 2 lots of 5 go through in an hour.

The problem is that water in a pipe has speed limits, and for ease of use, velocity could be said to be speed.

If the speed is to fast, it removes a protective layer off the inside of the copper pipe making it more likely to corrode. It also makes a noise as the greater friction in the smaller pipe resists the passage of the faster water.

But if it flows fast enough for you and the speed is acceptable it should be okay.

In general though, the longer the distance, the bigger the pipe you usually need and 65' is a long way.

 

[migoplumber]

if it was me, i would install a small 15l multipoint under the kitchen sink !

 

[stevetheplumber]

if it was me, i would install a small 15l multipoint under the kitchen sink !

just made me think do they still make oversink gas water heaters?