Electric shower stopped whilst kettle boiling

[chris1982]

This morning I was using our electric shower (Triton Enrich, 8.5 kW, 6 years old) when it virtually stopped. The flow reduced abruptly to a trickle, without a change in temperature, the on-light stayed on. I switched it off immediately. I ran a cold-tap to test the water supply but it was fine.

It then turned out that my wife had been filling and boiling the kettle in the kitchen (different circuit, of course) at that time. This never happened before (in the 4 years we've lived here). None of the MCBs or the RCD tripped and we did not see any lights flicker either. 5mins later the shower worked fine.

I think (but might be wrong!), the shower problem was not due to running the kitchen tap, as when running a tap in the bathroom or flushing the toilet, the shower flow gets hot, whereas here the flow virtually stopped but at constant temperature.

What does this fault point to? Is it a fault with the shower, the electrics within the house, or perhaps even the electricity supply to the house (overhead wire - on windy days the lounge pendant lights flicker)?

 

[terryplumb]

Did you try to use the shower after this occurred ,and is it working as normal now ?

 

[chris1982]

Yes, it is working fine now. But I try to understand whether it is safe and what the problem is.

 

[Taylortwocities]

The only thing I can think of is the busbar connection to the shower MCB isn't made properly and the extra current has broken down the connection.
You'll need a sparky to check it if it happens again.

 

[chris1982]

Thanks. But only if it happens again call the spark?

 

[terryplumb]

Sounds more like water starvation rather than an electric circuit issue.
See if the issue re occurs . Is the circuit protected by RCD or RCBO ?

 

[chris1982]

Thanks. It is protected by the main RCD and its own MCB

 

[chris1982]

The only thing I can think of is the busbar connection to the shower MCB isn't made properly and the extra current has broken down the connection.
You'll need a sparky to check it if it happens again.

And you think of the busbar connection as that is the only connection shared between the kettle and the shower?

 

[DetlefSchmitz]

I suppose it would be simple to repeat the experiment. Turn on shower then turn kitchen cold tap on full.

 

[terryplumb]

Do you have a combi boiler ? Multiple outlets drawing water at the same time would likely cause the issue, washing machine /dishwasher / toilets flushed/ taps running hot and cold etc.

 

[chris1982]

Thanks both. As the shower output remained at constant temperature I thought it is not that (typically it gets hot when flushing the toilet) and I ran the basin tap 20sec after the shower played up and it looked okay. Tonight I will experiment with the water anyway.

Yes, there is a combi boiler (installed in March, hopefully one day it will run the shower instead of the electric shower). There is only one bathroom and apart from the shower nothing was running there. My wife ran the kitchen mixer tap, not sure whether on cold or warm.

 

[terryplumb]

Let us know the results.

 

[Alec_t]

Sounds more like water starvation rather than an electric circuit issue.

Agreed, if drawing off water elsewhere causes shower temp to increase and shower flow to decrease.
I have a Triton shower and small changes in flow rate can cause significant changes in water temp.

 

[chris1982]

Yes I experienced that in the past but this morning the temperature did not change! Only the flow stopped, down to a trickle.

 

[terryplumb]

If it dropped to a trickle ,you presumably switched it off very quickly ? In which case the inherent heat built up inside the shower would have allowed hot water to trickle out for a little while .