I'm getting a new shower installed in my house, to replace the existing mixer shower. I am going to stick with a mixer shower, not least because I don't have a water tank. So, this means I have a high pressure system.
There are 2 pieces of terminology commonly used with showers – pressure, and flow rate. As I understand it, the flow rate determines how much water can pass out of the shower per minute, and pressure determines how much you can restrict the water's egress while maintaining the flow rate.
Now, I want to get the most powerful shower possible with my current setup. I understand that I am limited to the pressure and flow rate coming in from the mains because I have a high pressure system. In my experience, though, what makes a shower feel "powerful" is a third factor – the water velocity. The velocity of the water coming out of the shower head makes a major difference – if it's really fast, that's what I call powerful, as it can give a really nice massaging feel. That, combined with a good flow rate, is what I'd like to get. So, what should I do to get the best water velocity from my shower? Additional queries:
- Is it the shower head that would be best at giving a good water velocity? Presumably a shower head with fewer, smaller holes will restrict the water egress and force the water velocity to be faster in order to maintain the flow rate, assuming there is enough pressure? If so, what kind of shower heads would give this effect?
- Can anyone recommend any particular showers that are good at feeling powerful (basically, having a high water velocity to give a good massaging jet of water)? Conversely, can anyone give examples of showers that are designed to have a low water velocity?
- Is it possible that increasing my boiler size will allow a higher flow rate of hot water to pass through my shower? How can I measure what the maximum flow rate of hot water would be, and what the maximum flow rate of hot water is for my boiler?
- Why do different showers have different flow rates (sometimes quite significantly different)? It seems to me that the flow rate is basically dictated by what goes in to the shower – does this mean that showers with lower flow rates are artificially reducing the flow, and if so, why?
- In the UK, every store says it's "not possible" to use a pump (like you would with a low-pressure power shower system) with a high pressure system. Is there any technical reason for this, or is it purely a legality (it's illegal to pump from the mains because it would reduce everyone else's pressure/flow rate)?
The more detailed the answer, the better. I'd really like to get a good knowledge base built up of how to maximize the power of your mixer shower.
Best Answer
Official term is "water velocity" but for domestic plumbing this isn't really a thing you need to concern yourself with stick to pressure and flow rates. To answer some of your questions all in one: The flow rate can vary between showers due to the plumbing that supply's them also the pressure can vary for the same reason, they can also have water restrictors that slow the flow rate down.
In Australia this is due to regs stipulating maximum flow rates for water conservation reasons, ( I will always remove these as I hate a weak shower).
As for the flow rate you can use a flow cup to check the flow rate on a unrestricted tap and a pressure gauge to check pressure available.
You can attach a booster pump to your water supply but if this is legal in your location I do not know, the use of a booster pump will also depend on the supply pipe you have to connect to and what the pressure is already if it is near the output of the pump there is no point installing the pump.