Dingdongler

I need to buy an electric (not power) shower. I've decided on Mira since they get very good reviews.

The ones with the highest rating ie 10.8kw don't come with thermostatic control, the 9.8kw ones do.

So should I go for the lower rating and thermostatic control or higher rating and no thermostatic control?

Thanks

( the appropriate power cable required for 10.8kw is not a problem)

the shreksta

iTrader: (20)

Thermostatic all day long

piehole1983

iTrader: (7)

Do you have crap mains water pressure? If not, you wouldn't really need a thermostatic shower. I don't and mine is fine even when the dishwasher or something is on. My mums house is another story though, it's got a thermostatic shower as the water pressure is lower and is easily affected by other appliances.

dpb

Ok, I'll stick my hands up

Iv got a mira 8kw, and iv no idea whether it's thermostat controlled - i don't run other appliances, the dishwasher is awol presently only thing maybe is washing machine

imprezagaz

iTrader: (2)

Go with thermostatic. Will state minimum operating pressure in manual. Certain have safety cut outs to stop burning. Average house it 3-3.5 and I know Mira advance have to have a constant of 0.5 or they will cut out

imprezagaz

iTrader: (2)

I mean minimum of 0.5 to operate

Dingdongler

More confused now!

So are we saying that thermostatic control is only an advantage if you have low water pressure??

piehole1983

iTrader: (7)

That's not the only reason for it. It'll stop you from being scalded if for some reason your water pressure was affected badly somehow when you're in the shower. My point is if you have great water pressure all the time and your other appliances don't cause a loss of flow at the shower then technically you wouldn't need a thermostatic shower. On the other hand, it's a lot safer to have a thermostatic shower.

Like I said, I don't have a thermostatic shower and I've never had any issues with it. They all have a thermal and low pressure cut outs so if there's no water at all they'll stop dead. Also, make sure the power supply is protected properly by a RCD or similar.

ALi-B

iTrader: (1)

I think when it means non-thermostatic is that it has a temperature control by altering the flow rate. Certainly our old electric shower was like that (and it was a pile of poo, so was binned - never seen a electric shower that I could class as adequte interms of flow rate IMHO )

It however will always have a high-limit thermostat to prevent scalding. All electric showers have this...even the 20yr Santon I used to have to endure (and proudly smashed up when we had a new bathroom fitted )

The issue is I guess is if someone flushes a tolet or the washing machine decides to fill up, if the mains plumbing is inadequate, you'll get a hot shot of water when the pressure drops (like the Combi in my old house used to do before I fixed with a 22mm direct from stop-**** to boiler with full flow-valves). If you have 15mm into the house, which firstly goes through a kitchen and/or downstairs loo before reaching the upstairs bathroom, then its likely you'll suffer the same annoyances as I did (as water will always take the path of least resistance - which is NOT the shower).

piehole1983

iTrader: (7)

This is true, manual temperature control. But my mums has a manual control too and it's thermostatically controlled stopping you from turning it up too high and burning yourself and also helps with pressure dips. You really need more than 10kw to maintain good heat and water flow at the same time.

b3nmw

Make sure there's an rcd fitted as well m8

Mouser

I would go for the highest rating shower in order to maintain a more powerful stream of hot water especially during the winter months.

Dingdongler

Thanks, yes I've ordered a 10.8kW Mira one without thermostatic control.

Henrik

iTrader: (5)

10.8kw is a beast of a shower, hope your mains power supply is up for it.

We have a 10.5kw, which draws 45 amps, and i've had the main fuse blow once already, so now we can't use the kettle at the same time as someone is having a shower, which is annoying, frankly.

dpb

Not on a different circuit Henrik??

f1_fan

iTrader: (9)

Your main fuse is not of an adequate rating, but maybe the whole consumer unit is not rated high enough either so I would be careful about replacing the fuse with anything larger.

If I were you I would get it checked out as you don't want an electrical fire for the sake of a couple of hundred quid.

dpb

Ours is 100amp

45 doesn't sound likley

Dingdongler

I'm having some new wiring and new consumer unit fitted so I'll get it checked.

markjmd

iTrader: (11)

The main issue would likely be that the individual RCD and the pull-cord cut-off switch are both rated too low, since these are normally 45amp each as standard for showers. Wiring from RCD to shower may also need upgrading though.

dpb

You need a shower pull cord switch as Well as rcd.??

I don't

f1_fan

iTrader: (9)

An electric shower should have either a pull cord switch or a wall mounted switch outside the bathroom. Also anything over 8.5kW really needs 10mm2 cable rather than 6mm2.

dpb

Got switch outside bathroom, yes was forgetting.

I must turned it off when wiring in new unit. Haha

f1_fan

iTrader: (9)

Henrik

iTrader: (5)

The main fuse board is fine - it's up to 17th regs. The issue is with the supply coming into the house, and me not being prepared to rip up my drive, floors and pay 1200 pounds for the privilege to EDF, and then in addition having to shell out for having an electrician on site to do the connection from the main fuse to the fuse board. We just don't put the 3kW kettle at the same time now, and don't blow the main fuse.

Once we get the loft done, we'll probably go for a new boiler system anyway, so will sort non-electric showers out at the time as well.

Henrik

iTrader: (5)

In hindsight, though, I should have checked my main fuse rating before getting a 10.5kW shower...

10.5kW is an insane amount of electricity, really, especially when you look at how small the shower units look. 10.5kW is like a decent size industrial welder running at full pelt

piehole1983

iTrader: (7)

Main incoming fuses are between 80A and 100A, also the mains incoming cable will normally be tri-rated to cope.

Henrik

iTrader: (5)

Mine's 60, so it varies depending on when your house was built etc etc. The largest EDF will supply to a single dwelling/board is 100 amps, apparently.

Anyway, moral of the story is: Most houses will probably be OK, but if your house is from the 30's (say), then it's possible that the incoming cable is not thick enough to support more than 60 amps, in which case, don't be greedy on the power, or be prepared to shell out a lot of money to have the cable uprated (here there's a caveat: sometimes the incoming cable is thick enough to support a higher rated fuse, in which case it will set you back ~180 quid to have the (main) fuse box uprated).

Dingdongler

Well it's been fitted, the existing cable was already 10mm.

It'll be interesting to see what happens when it's run at the same time as 100m2 of electric underfloor heating!