Water heating problem

[Paul19781978]

I have a Worcester Bosch 28 Combi boiler which was fitted new 6 years ago.

Over the last few weeks I have been getting initially hot, but then lukewarm and cold water from the taps & shower. The heating system is working fine.

I'm not entirely sure where the problem is but I feel it may be the heat exchanger or a diverter valve.

Is there any one who can kindly explain to me what is going on and what I need to do to rectify this problem?

Thank you kindly.

Paul

 

[45yearsagasman]

Exact model please. A 28 what? Cdi or?

 

[Paul19781978]

Worcester Greenstar 28i Junior

 

[Boilerman2]

Possibly Thermistor fault? (quality boiler!!!....not!)

 

[Agile]

I think this is possibly a four pipe heat exchanger design.

In which case it could be a thermistor failing when hot but it could also be one of several other problems.

The thermistors are relatively low priced but like all boiler repairs are best only replaced if diagnosed as faulty.

What happens next if the boiler is left with hot running after it goes cold?

Tony

 

[Paul19781978]

When the water is running the temperature if the water fluctuates between burning to lukewarm to cold and back to hot!

Could this be a problem with sludge in the heat exchanger?

Maybe it would be a good idea to clean this out (eh X400) prior to fiddling with the thermistors?

 

[Boilerman2]

I don't think that Workchester make a Condenser with a 4 pipe heat exch???

 

[Agile]

If the boiler has a plate heat exchanger then thats a classic description of a blocked unit !!!

But like anything else a proper diagnosis is required to treat properly.

A thermal survey will usually identify the problem.

Tony