Hot water not so hot Combi Boiler

[Haydns]

Hi,
My CH seems to be working fine (rads piping hot), but the direct hot water has definitely gotten cooler over the last few weeks, and now is it fluctuating between reasonably hot and luke warm while the tap is running. Its got to the point were we can't fill a washing up bowl with sufficiently hot enough water.

Any thoughts on what it may be before I get a plumber round?

The boiler is chaffoteaux & maury Britony 80.

Thanks for any advice
Haydn

 

[BARNY78BG]

hi, hot water issues on combi's are rife in cold weather, they come thick and fast, does the water stay hot if you throttle the tap back to get a slower rate of water? or does the boiler fire up and shut down repeatidly?

 

[Haydns]

Thanks for the reply,

The water doesn't seem to get any hotter if I throttle the rap back, seems to be doing the same hot(ish) / luke warm cycle whatever the pressure of water coming out of the tape.

Just taken the cover off the boiler, I can see that the flame on the burner is increasing an decreasing cyclicly (hence the temp fluctuation).

The boiler did stop working last week, but a quick clean of the pressure switch tubes seemed to have it sorted it. Could it be related, a faulty pressure switch giving the wrong signals?

Cheers
Haydn

 

[linkyplumb]

Possibly the plate heat exchanger starting to scale up