Fitting a power shower.. Help!!

JohnOfLeeds

Hi MSExperts :money:

Wondered if anyone can help. (And sorry if this has been covered)

Just moved in a new house and it has an electric shower that is very slow (Mira Go).

I presume the best fix for this is buying a power shower?

Is it as easy as just taking the old shower off and sticking a new one up? Or do I need to run cables/alter plumbing etc? How much would a plumber cost to do such a job?

Thanks in anticipation :beer:

C_Mababejive

What sort of boiler do you have? Do you have a hot water storage cylinder?

macman

By 'power shower', do you mean a more powerful electric shower? Or a pumped conventional shower? The latter requires feeds from a hot and cold tank-do you have these (you won't if you have a combi boiler)?
If you want to upgrade an existing electric shower, then you may need to uprate the circuit cable and RCD-it most certainly isn't just a case of 'sticking a new one up'.

JohnOfLeeds

I think its a Combi boiler (I dont even know what that means!) its a Greenstar 24i Junior.

I dont know what I mean - Whatever is going to give us a powerful shower!!

Thanks For your help

WestonDave

Mira Go is an instant heat electric shower which works on cold feed only.

First thing you need to do is establish which one you've got - this time of year the 8.5kW one will give you a dribble. This is because the feed water is very cold, and they work by controlling the rate at which the water runs over the heater - lower flow equals hotter as it has more chance to heat it up.

The easiest option would be to swap a low rated one like that for a 10kW shower but you can only do this if the cable from the fusebox/consumer unit is sufficient. If you are lucky someone has stuck a cheap shower on a compliant cable - but I suspect its far more likely the cable isn't up to anything more powerful and putting a more powerful shower on it will cause overheating and a risk of fire. Do not do this! You'll need to get the circuit checked by an electrician to see what it will take.

Switching to a dual feed shower heated by the boiler will avoid the cable problem but will require a hot feed to the shower as it will currently only have cold. These generally have some kind of mixer valve which mixes hot water from the boiler and cold water from the mains. With a combi boiler your flow will be limited by the rate that the boiler can heat water so I'd expect this to be better than an electric instant heat but not stunning.

The other alternative is to run a mixer shower off a hot water tank, however here you can run it as fast as you like provided the tank doesn't run cold. In our previous house we had a lovely Aqualisa Quartz shower that in turbo mode could take the skin off your back - the downside was it could run the tank cold in about 10 minutes at that pace, so you need a big tank of hot water to use one which might not be that great for energy efficiency.

JohnOfLeeds

Wow... Thanks for your help. Great answer.

Though would have preffered "Yeah stick one up"

Cheers

diywhynot

JohnOfLeeds wrote: »

Hi MSExperts :money:

Wondered if anyone can help. (And sorry if this has been covered)

Just moved in a new house and it has an electric shower that is very slow (Mira Go).

I presume the best fix for this is buying a power shower?

Is it as easy as just taking the old shower off and sticking a new one up? Or do I need to run cables/alter plumbing etc? How much would a plumber cost to do such a job?

Thanks in anticipation :beer:

Assuming you have a bath, replace the taps with a bath shower mixer (runs off the combi).

C_Mababejive

To have a "power shower" experience with the equipment you have is going to cost ££££

macman

You can't install an electrically pumped 'power shower', because you have a combi boiler-so not hot or cold tanks. The hot water in a combi is heated 'on demand'-none is stored.
The flow and temp you would get with a mixer shower are dependent on the water pressure and flow rate of the combi-your plumber will advise.
Once the weather gets warmer, the flow rate of your existing shower will improve, as the incoming ambient water temp is higher, so the water will get up to temp faster.
Or upgrade the electric shower with the circuit rating proviso already given.

C_Mababejive

#9 What Macman says...incidentally and with regard to the growth of combis,in this current cold snap there are some people who cant use their combis at all or at best,they can use them with reduced output. Why? There isnt enough gas to go round and pressures are dropping at periods of peak demand. Some combis wont tolerate it and lock out whilst others soldier on at reduced output.

lemon26

We recently replaced our 8kW Mira with a 10.5kW Creda shower (although they're all very much of a muchness) and needed thicker cable and a new circuit breaker as the old ones weren't up to task..

As a very rough guidline, use P=VI re-aranged to I=P/V, with P being the power (W) of the shower and V being 240v (UK mains). For an 8kW (8000 W) shower you'd need cable and breaker that could carry 33.33A and for a 10.5kW shower you'd need something that could handle 43.75A.

Our electrician came and put in a new MCB and cable for £50 on a sunday - I helped him run the cable as it was quite long.

Hope this is of some use...