Shower keeps going cold

[ukmercenary]

Hi

So I have a less then a year old bolider 'Worcester Bosch 25 Si compact boiler'
My house is just a small 2 bedroom house.

The shower is a Mira Coda Ev2 Shower (its a thermostatic shower)

The problem is that the water will go cold when im having a shower it only lasts about a minute but its enough to be really annoying. It's enough to make me step out the shower whilst it goes cold.

I really need to fixed ASAP as ive started to let my spare room out on AirBnb.

Any ideas?
My cousin said try turning the water temp up on the boiler which I have done but it makes no difference. The only difference been is now the hot water tap is boiling hot which I think is almost a H&S issue.

Anyway and ideas?

 

[Madrab]

Does your bolider ( boiler) shut off, then the shower goes cold, then fires up again?

 

[ukmercenary]

Does your bolider ( boiler) shut off, then the shower goes cold, then fires up again?

I don't know to be honest as i live alone

 

[Madrab]

Can you turn on the shower (don't get in) and when it starts to go cold quickly go and check the boiler or get a pal and shout when it goes cold?

 

[ukmercenary]

Can you turn on the shower (don't get in) and when it starts to go cold quickly go and check the boiler or get a pal and shout when it goes cold?

Ok so i turned the shower on and waited for it to get cold then ran down stairs and the boiler light stays on.
I then decided to stay down stairs and watch the boiler light whilst the shower was running.

Sometimes the boiler light does turn off however if i run up stairs the water is warm still.

I don't understand

 

[Madrab]

It takes time for the non heated water to get to the shower so you may find that your timing isn't right to get to the shower when it's cold. Does the shower do this regularly, in other words when you're in the shower does it cycle from hot to cold and back to hot more than once?

Are you in a hard water area?

 

[ukmercenary]

It takes time for the non heated water to get to the shower so you may find that your timing isn't right to get to the shower when it's cold. Does the shower do this regularly, in other words when you're in the shower does it cycle from hot to cold and back to hot more than once?

Are you in a hard water area?

Yes it is doing this regularly not sure if it is in a hard water area im in Reading Berkshire. Could it be a problem with the boiler?

 

[flameport]

Berkshire is a hard water area.
The heat exchanger in the boiler is probably coated in limescale. It's an inevitable problem with combination boilers.
It can probably be descaled.

 

[ukmercenary]

Berkshire is a hard water area.
The heat exchanger in the boiler is probably coated in limescale. It's an inevitable problem with combination boilers.
It can probably be descaled.

The boiler is not even a year old and our plumber fitted a limescale inhibitor ?
When I turn on the hot water taps I can't replicate the problem surely if it was limescale problem the taps would go cold too?

 

[flameport]

Yes, it would affect the hot taps as well.
It may be the shower itself which is scaled, they can usually be dismantled and cleaned.

What exactly was the ' limescale inhibitor ' that was fitted?

 

[ukmercenary]

Not sure to be honest. I just don't want to have spend a fortune on a plumber for him not to even resolve the issue.

 

[gigz]

First thing to do is take the shower head off and do the above test again. What sometimes happens is the flow is restricted by the shower head and the boiler temporarily overheats, cuts out, then cools and starts again. Turn the DHW temp back down to suit your taps.

 

[transam]

plate exc' may have carp in it on primary side ?

had the issue a while back on a 32 Kw combi in a tenanted prop kept shutting down after 5 or 6 mins when shower running
put a bigger plate exc' in it in eventually

 

[ukmercenary]

First thing to do is take the shower head off and do the above test again. What sometimes happens is the flow is restricted by the shower head and the boiler temporarily overheats, cuts out, then cools and starts again. Turn the DHW temp back down to suit your taps.

I will try this this weekend, another problem is the boiler keeps on loosing pressure as it seems almost every 2 months I need to top it up is that normal?

 

[ukmercenary]

plate exc' may have carp in it on primary side ?

had the issue a while back on a 32 Kw combi in a tenanted prop kept shutting down after 5 or 6 mins when shower running
put a bigger plate exc' in it in eventually

Sorry I don't understand this technical plumber talk