Mira Sport 9.0 Electric Shower Not Getting Hot

[chaoticj]

Hi,

We have a Mira Sport 9.0 electric shower in the bathroom - it's not getting hot, the water is barely lukewarm and with winter approaching isn't ideal.

If someone flushes the toilet or if you run a tap - it gets warm. This was the case before but it would get scalding hot. I believe it's normal for an electric shower because less water going into the shower means the water gets hotter.

I'm not sure if it's a coincidence but we had a replacement combi gas boiler fitted a few weeks ago and the issue seems to have started around then.

Just wondering if anyone has some ideas what may be wrong or what to try?

Thanks in advance,
chaoticj

 

[CBW]

It’s probably coincidence with the boiler, and likely the head and hose could be blocked, check the incoming filter in the shower, could even be heating element in the shower. What setting is the shower on, eco or max?

 

[chaoticj]

Thanks @CBW I will have a look. The shower is on max.

 

[chaoticj]

I forgot to mention @CBW the big knob you use marked 'temperature' when turned an amount makes a 'snapping' noise, as though it's resisting.

How would I check the inlet? Isolate and cover off?

I've disconnected the shower head and hose, it all seema clear.

 

[Johntheo5]

In this weather with the mains temp around 18C you might be better off running on 1/2 power which ic actuay a lite more than this and you should/might get - 65% of the full power flow rate but more consistent. Theshowershould flow - 7/8LPM at the fully cold setting. Cleaning the shower filter may also help.


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[CBW]

How would I check the inlet? Isolate and cover off?

Yes, it’s on the cold inlet, but isolate the cold first, or you’ll get wet. As for the clicking, it might not be moving correctly. Try running without the head and hose, see if that makes a difference.

 

[fixitflav]

when turned an amount makes a 'snapping' noise, as though it's resisting.

That doesn't sound right. Early electric showers (I believe, I've never had one) worked at full power, the temperature being adjusted by varying the water flow. Modern ones (again, I believe) have adjustable electric power. But if you have set it to Max, and the flow is low, but it's only lukewarm, it clearly isn't getting 9 kW into the water. Maybe the control is jammed in some way.

 

[Johntheo5]

I have one of those showers (now 16 years old). There are 3 heat settings, cold, one heating element on, & both elements on, with either one or both elements selected, 5kw or 9kw, if the water temperature reaches 48C then thr thermal cut out, TCO, (Duo disc) switches off the power and switches it back in when the TCO resets, the temperature will cycle very hot/very cold but won't run lukewarm, should this TCO fail then another one contIned in tbe same sensor switches to switch out the power permanently at 72C and requires TCO renewal.
There are two indicating LEDs, one indicates power on the other only illuminates permanently if the flow/pressure is too low and switches out the power, it's possible but unlikely IMO that this is switching the power on/off if borderline pressure resulting in lukewarm water. Every time you press the start button (even with healthy shower) you will see it flicking on for a second or so until the flow switch closes the heating elements micro switches. So advise again, measure flow rate and observe this LED on start up and then at 1/2 and full power.

 

[chaoticj]

Hi,

I've been meaning to post an update - I fixed the electric shower before Christmas.

I watched a YouTube video where they went through testing with a multimeter for common faults.

First turning off power and water I then checked;

- On/off switch - continuity with buzzer sound - test across the 2 terminals - when ON should buzz, when OFF should be silent - OK
- Solenoid valve - continuity - test across the 2 terminals - should give a kOhm reading - OK
- Thermal cutout - continuity with buzzer sound - test across the 2 terminals - should buzz - OK
- Heating element(s) (there are 2 of them) - test across the terminals - should give Ohm reading on each - OK

So I then thought, as the temperature dial (controls the flow valve) was making a cracking noise and turning the bathroom taps on full made the water to the shower hot - it was probably the flow valve. Turning the taps was crudely adjusting the flow of water into the flow valve.

Replaced the flow valve and the water was piping hot - scalding! hard to control. The hardest part of replacing the flow valve was removing the old one/connecting the new one to the inlet. The instructions showed taking most of the shower apart. I managed to gently turn the inlet slightly clockwise which allowed me to remove the old flow valve and insert the new one and avoiding some serious disassembly.

I realised looking at the back of the front panel that there were some tiny bits of broken plastic. Slowly turning the dial and watching the inside, I could see it was not moving and then moving a lot - apparently the flow valve seizes up and then as it becomes harder to turn, it breaks the front panel dial, affecting it's movement and making the cracking noise.

So I got a new front panel and an inlet filter (as it had disintegrated trying to clean it) and now everything has been working perfectly the past weeks. Some of the parts were cheapest from Mira themselves but it's possible to find them on eBay sometimes.

Many thanks,
chaoticj