Mira Sport 10.8kW

[SnackAttack]

Hi, I am new to this site. Sorry if this sounds thick but....
With a Mira Sport 10.8kW shower you should have a 45A fuse, however i seem to have a 40A Wylex MCB. Will this affect the performance of the shower?

 

[JohnD]

Yes, it means it won't work.

 

[JohnD]

To be a bit less unhelpful:

The shower, at high heat, will use about 46 amps. The MCB, which works rather like a fuse, will safely carry only 40 amps. If you ask it to carry 46, it will think there is a fault leading to an overload, and will cut the circuit.

There is a little bit of leeway and delay depending on the size of the overload, but that's about it.

It might be possible to fit a higher capacity MCB, but that is subject to the capacity of the cable and the other loadings on your domestic installation.

edited to say, and if you tell me it is already installed and working perfectly, I will mumble something about tolerances and variations, and walk away briskly

 

[SnackAttack]

Ok....... I have already got it fitted. The reason I ask is because I am having trouble with the shower itself. If i press the high button and turn the temperature dial upto full heat, it is only just hot enough for a shower surely it should be boiling!?

 

[JohnD]

2 possible reasons:

(1) In winter, like now, the incoming water is colder, so even though the heater raises the water temperature by x degrees, it has a lower start temp, and so a lower finish temp.

(2) the shower heater probably has two heating elements, you can usually control th heat by switching on the smaller, or the larger, or both. Sometimes one of these elements failed.

But at this tme of year it's probably (1)

 

[SnackAttack]

Thanks JohnD. So nothing to do with 40A fuse. Anyway do you know of any way to raise the temperature so i can at least have a nice hot shower on these cold mornings?

 

[JohnD]

Wait for the warmer weather, or reduce the water flow. Less water for the same electricity means it'll be hotter.

See if the temperature control does appear to increase the temp, or if it has a plateau, say, half way round the settings.