Boiler Problem.

[Zubar]

Hi,
The water coming out of our hot tap is warm, whereas it used to be extemely hot!! I have turned off the boiler and then reset it as per instructions, but it still isn't heating up the water properly!! We have been told by EDF that it could be the thermostat and that isn't covered on our service contract ( what a suprise!!). Any ideas in regards to anything else I can try, before I fork out £80 for somebody to look at it before they even attempt to repair it!
Thanks.

[AlBags]

What type of CH system exactly?
What TYPE (ie Combi) make, and model of boiler?