I have every reason to believe that Mira make good electric showers and they certainly make good mixer showers. I have been asked by 3 customers with Mira Electric Showers in the space of a week as to the possibility of improving the pressure upstream of an electric shower. For this reason and for the benefit of my customer service team, I am replying on line, with this post.
I worked for many years for Anglian water and other Water Companies and I was responsible for taking out water tanks and replacing them with pumps. I get a bit prickly when I am told that you can’t boost the pressure before an electric shower because you can, and I did this for 1,000s of Anglian Water customers. The only difference between boosting an entire neighbourhood or just one shower in your home is a matter of size, Anglian Water had big pumps, I sell micro pumps, the electric shower simply reacts to pressure, not the size of the pump.
Mira Sport Showers are sold with two power outputs. The 10.8 KW electric shower is the bigger of the two Mira Sport showers.The 10.8KW shower needs a minimum of 1.0 bars unlike the 9.0 KW shower which only needs 0.7 bars.
With more powerful electric showers the pressure required is greater and because the flows are greater the boost a pump gives is less.
The general rule is that you have a 9.0 KW electric shower you need a single boost SP2B. If you have a 10.8 KW shower you need a SP21S.
The flow rate from a Mira 10.8 KW is stated by Victoria Plumb to be 4.89 litres a minute so assuming this to be correct each of my pumps will give 0.35 bar support.Two pumps will give 0.35 + 0.35 bars = 0.7 bars.
Assuming the pressure does not fall below 0.3 bars then 0.3 + 0.7 = 1.0 bars.
If the pressure falls below 0.3 bars my solution will not work. If the pressure does not fall below 0.3 bars my solution will work.If you want a cold shower the pressure will fall further than if you want a hot shower.
Because the upstream pressure is uncertain, there is no guarantee that if you start with a SP2B (£125), you might have to upgrade with a SP1U to a double boost (£55). If you start with a SP21S you may solve it with just one pump.
You will find that showers using an electric shower will cost 57p per shower , if you heat water using a gas boiler its 20p. If you decide to replace the electric showers we are happy to help.
Kind Regards
Alan Wright
