Increase water flow rate

nick_a

Hi, we are in the process of refurbing our bathroom and ensuite. We get ok flow rate in our bathroom of 10l per min but only get 5l per min in our ensuite.

System is a gravity fed system. We can’t increase the flow rate too much as we have a tank that is only about 100l.

Anyone know how to increase the flow rate in the ensuite to about 10l per min?

Thank you.

Heedtheadvice

Given a constant pressure (head) the flow rate is dependant upon resistance in the pipes and fittings.
Several factors come into play such as pipe diameter (baths often fed via 22mm pipes, sinks etc. by 15mm pipes. Check yours.
Distances as longer pipes have more resistance. Is the ensuite pipe run longer?
Twists, turns and joints give higher resistance to flow. Compare the pipe runs.
Valves and narrow tap piping also similarly reduce flow, as will blockages from soldered joints with excess solder.

All these can be cumulative but the starting point should be pipe sizes and tap constrictions. Many a modern tap have very narrow pipe tails whereas baths tend to have individual 22mm feeds right to the taps! Narrow tails are Ok for high pressure mains feeds but not so good for low head gravity feeds.

Find the reason for the lower flow/higher resistance and you have the answer as to what you might be able to do about it!

nick_a

Sorry it has taken me a while to reply. The pipes leave the cylinder at 22mm and then split to go to each shower and run at 15mm. The shower with the lesser pressure has a run of about 3-4m at 15mm pipe. It turns twice. The pipe to the better shower runs for less than a meter at 15mm.

How would I check for tap restrictions?

Thanks for your help.

Nick

Heedtheadvice

My comments on 'tap restrictions' usually apply to sink taps such as where you have modern mixer types. If you can get to the final pipework connected to the taps then there may be a narrowing final connector pipe (less than 15mm) that is part of the tap assembly that screws in to the tap base.

That restriction does not apply normally to showers.

If there is a big difference in the shower flow rates (you might expect some owing to the extra you mention) if they are thermostatic mixer showers, there might be some blockage debris in the filters to either the hot or cold. Even one filter with some restriction will limit the flow as the thermostatic mixer tries to keep the flow at the correct temperature.