boilerplumbingshower
I all, I'm looking to purchase a new shower for my combi boiler and am looking to maximise water pressure output.
I'd like to know what one produces better water pressure? Mixer based or TRV controlled showers?
And are there any after market products that can boost the water pressure for a combi boiler system? Many Thanks
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.
Years ago I had one of the first high efficiency gas boilers. It supplied an air-handler for heat and a heat exchanger for hot water. Because back then this kind of boiler would breakdown about 2 or 3 times a year, I installed backup electric heat in the air-handler and a backup electric 30 gallon hot water tank.
I plumbed the hot water tanks in parallel with separate valves to both and normally just kept all valves open and the breaker off to the electric tank until needed. It was amazing how the two tanks acted as one with just gravity flow for one tank to heat the other. If I hadn't experienced it for many years I wouldn't believe it could work so well.
If you added a small electric tank, you'd increase the amount of stored hot water to buffer the times of high usage. And you wouldn't even have to run electric to it, but if you did you'd also have electric auxiliary hot water.
Best Answer
Neither of those should have a noticeable impact on water pressure, that's up to your bladder tank, or the line pressure from the utility.
You may consider using a more efficient showerhead, which typically reduce flow, but increase pressure. Unless you're trying to fill buckets in your shower, this will probably be your best bet.