Hot water not hot enough?

[banjo13]

Could anybody help me
I had a worcester greenstar 30si combi boiler fitted oct 09. Its been fine up until approx 3 weeks ago. When the hot water is run, either for a bath or washing up. Its cool enough to sit in straight away. You don't need to add cold water. The dial is turned to max. This happens when the heating is off or on. Last year when the winter was colder I still had to add cold water.
Anyone got any ideas.
Thanks, Banjo.

 

[Agile]

Turn the tap only half on and the water will get hotter!

 

[banjo13]

why should I need to do that, I didn't a month ago. What has changed?

 

[banjo13]

Has anyone else got any ideas please??

 

[buntzsenior]

I have the same problem,24i worcester combi all of as sudden the hot water wont come through hot enough,the central heating is still working?? any help please would be appreciated.

 

[moggridgeplumbing]

Your boiler is set for a certain flowrate at a set temperature. If you exceed that flowrate by turning the hot tap fully open then the boiler cannot reach that temperature. By reducing the flow at the tap the boiler can heat the water at the temperature you want.

 

[Ihavenojob]

Has it been serviced at all? If the CO2 readings are out it can cause problems.

 

[rcoverson]

So the answer after checking there is no flow ristriction through the DHW system(ie plate heat exchanger) and you have the correct mains inlet pesure is to see what the boiler parameters are set at. If its a new boiler you will have a benchmark form filled in, check it matches with what is in the manifatures instuctions.

 

[Maxsys]

If its anything like my 28CDI then it could be a blocked plate exchanger, or a DHW thermistor, i would suggest you get and RGI in to find out what it is.

Do you have inhibitor in the system? And when was it last serviced?