problems with thermostatic shower

[tabita]

Hi all,

I have a problem with the hot water from my shower which is equipped with a thermostatic mixer valve. I used to shower at 37C. But lately, the boiler would not kick in until I turn the knob to 40C, which is too hot for me. Any less than 40C and the boiler would stop.

Can anyone advise me what the problem is please? Thank you!

 

[tabita]

I suddenly wonder, could it be related to limescale build up?

 

[Madrab]

Depends where you live, if you get limescale buildup in say your kettle, then yes it could be restricting the plate heat exchanger in your combi boiler or within the shower.

 

[tabita]

Yea, I'm in hard water region unfortunately.
Is there a way to pin point whether it's the boiler or the shower?

 

[Terry7556]

Compare what's happening when you use the other hot taps in the house
Do you get the same result

 

[mogget]

It might be that the incoming water is warmer as it's summer and if the shower doesn't have a fast flow it could drop below the boiler's minimum output.

OP, it may help if you tell us the make and model of the boiler and the shower flow rate in litres per minute. It could be as simple as limescale in the shower head reducing the flow.

 

[tabita]

Hi all, thanks for the replies. I am away atm, but will post the make/model of the boiler and shower litre per minute soon.

The hot water from the kitchen and toilet taps are working fine. It is only the shower which is experiencing the too hot/too cold problem. This makes me think it is a shower problem rather than a boiler issue. I just hope it isn't in the shower tap - I wouldn't know how to change the tap!

 

[Terry7556]

Tabita when you get back unscrew the shower head from the hose and point the hose into the bath with the hot running​

See if it still happens, check the shower hose for kinks / flat spots
Mogget has pointed this out to you in the post above yours