I am considering Mazuma Power Stream Plus2 8,000W for my bathroom (baht, shower and sink). 

 

I would appreciate recommendations. Thanks

We have one, most effective.

 

You will need a mixer tap on the shower.

 

Is the wiring already in place? If so then if it's smaller than 4mm² you need to replace it, if wiring new I would go with 6mm².

Thanks. It will be all ne electrical wiring. 

Plumber tells me that  Mazuma Power Stream Plus2 8,000W  not supply enough hot water to fill bathtub 

18 minutes ago, CNX69 said:

Plumber tells me that  Mazuma Power Stream Plus2 8,000W  not supply enough hot water to fill bathtub 

 

Since it will supply hot water for as long as it has power and water I don't see the issue unless you want a scalding bath.

 

You could get a large storage type heater, less power consumption over a longer time and, of course, once you've used all the hot water there's no more.

 

What is the plumber recommending?

 

On-demand heaters with more oomph will need 3-phase power or be LPG (care with ventilation).

Thank You Crossy, The power is 3phase, i will tell her about storage type heater

Will the water only supply the bath / shower? 

 

Although UK centric this page should give you an idea of how big a tank you would need 

https://www.hotwater.org.uk/sizing-a-hot-water-cylinder/ 

 

You're probably looking at the 60L models running at 60C if just the bath, 100L version if it's doing other domestic hot water too.

 

Meanwhile, if we assume an incoming water temperature of 25C and a bath temperature of 40C (delta t 15C) and bath volume of 100L then the 8kW Mazuma would take 15 minutes to fill the bath so your plumber is probably right (we don't own a bath, showers all round).