Flash heater shower not controllable

[Gwynston]

We have a 15-year-old shower which doesn't seem to graduate the temperature very well. It's a fairly basic flash-heater type, with just a single cold mains input.

This time of year it seems very hard to control - it's either too hot or if you turn it down just a bit, it doesn't heat at all. In the winter when the feed is colder, it's a bit more controllable, but obviously the pressure drops quite a lot as it needs more time to heat.

I haven't taken it apart for a look, but I'm wondering if there are any serviceable parts in such showers, or whether there's any routine cleaning/maintenance I can try on it?

 

[Dan Robinson]

Make and model?

I assume you mean electric shower?

 

[Gwynston]

It's a Mira. I can't remember the model off-hand. Will check later.

And yes, it's electric - I'm not aware of many flash heater showers that warm the water by means of coal, wood etc.

 

[Gwynston]

It's a Mira Zest (J96E) 8.5kW 1998-2004 :
http://www.showerreplacementparts.co.uk/shower-spares/mira/electric-showers/mira-zest-1998-2004
https://www.showerspares.com/mira_shower_spares/mira_all/mira-zest-mk1-1998-2004-zest/

Just wondering if there is any straightforward cleaning/maintenance that I might be able to undertake myself to improve things?

 

[Madrab]

And yes, it's electric - I'm not aware of many flash heater showers that warm the water by means of coal, wood etc.

I reckon the question was due to the fact that I've never heard of an electric shower being called a flash heater before either but in this game....never say never ... ergo I guess the need for clarification.

Nothing really to service - apart from the filter. You could try a new shower hose and/or head as they sometime cause an issue with pressure but no guarantees.
A 15year old electric shower will be at the end of its life really, chances are the elements are tired as well as the controller. All you could do is replace parts. It owes you nowt really, time to replace IMO.

 

[Gwynston]

OK, sorry for the poor terminology. I was trying to differentiate between an electric power shower which uses standard hot and cold feeds and has a pump for higher pressure. We have one like that as well as the one I'm talking about which just heats the mains cold feed instantly.

I'll take a look to see if the filter needs cleaning.

 

[HootingOwl]

Instantaneous Electric Shower is what they are called around here. Not worth repairing this as it is at least ten years old. The shower head and hose will be dilapidated by now. You can try descaling the heater can - but you are pretty much urnating into a stiff breeze.

 

[AGAS]

And yes, it's electric - I'm not aware of many flash heater showers that warm the water by means of coal, wood etc.

flash heater showers are used with instant water heaters and rarely used