No Hot water in Top floor shower

[chiraju]

Hi
We bought a town house just 6 months back and till now we had no problem. The house is a new construction by David Wilson (but we bought it second hand from a previous owner). The first 2 year warranty ran out last month in Jan and now we have a problem. Would need some special Advice.
Problem:
No hot water in the 2nd floor en-suite shower (But hot water is fine in the same en-suite sink).

Steps I have tried:
1. Switched on the shower, turned it to full hot water (the water was only lightly warm)
2. Turned the cold water tap in the sink and also in the first floor Bath / Sink
3. Ran back upstairs en-suite room and the shower had Hot water coming.
So I understood that when the full cold water pressure is running in to the shower then the water is not hot (or slightly warm) and when the cold water pressure is distributed then I am getting hot water in to en-suite shower.

Installation details
This is a David Wilson built town house, It has 3 floors including ground floor
Ground floor - there is a Boiler
2nd floor there is a big immersion tank
There is a pressure gauge next to the immersion tank, but this is only for Central Heating it seems (confirmed by David Wilson customer support)
I can't find any other pressure gauge which shows hot water pressure.

Any help is appreciated.

Thanks
Raj

 

[Plumbstar Tom]

what is the make and model of shower?

it will probs still be in guarantee with the manufactuerer

 

[chiraju]

Thanks Tom.
The shower is under warranty, But they said that if it is due to hot water pressure then they can't do anything and then above that they will charge me £120 for the visit. So They asked me to check few things like turning the cold water on every where and then see if I get hot water (which might mean hot water pressure). I am just confused and trying to understand what is the problem and who can solve it. I don't want some one to just walk in and say well this is nothing to do with XYZ and you have to call ABC to fix this and charge me some £*** to say that.
Hope this is Clear.

 

[stevetheplumber]

if theres water at the basin in the same room its most likly theres water to the shower check by cracking the inlet nut on the shower to see if theres water there if it concealed in wall usually you can acces these by removing the facia plate

 

[dontknowitall]

Is it a mixer or electric shower?