Baxi combi 130 HE not producing a constant flow of hot water

[stephenthomson10]

Hi

This boiler has kept British Gas servicemen off the streets ever since we moved in 3 years ago and took out one of their service plans. It's now 6 years old but most of the internal parts are much newer!

The latest issue is that the hot water temperature has started to fluctuate quite noticeably. One of our thermostatic shows has been running cold after a few minutes and what is happening is that the boiler is running for a few minutes, getting the water up to the preset temperature but then shutting down, then coming back on straight away to a few seconds but then cutting out again in a cycle. The output water temperature obviously drops and the cycling only keeps it around 38 rather than about 48.

Interestingly different taps behave differently. The kitchen tap (near the boiler) is fine. In the bathroom directly above the boiler the basin and shower are fine but the bath causes the cycling and the en-suite which is next to the main bathroom (so I guess at the end of the pipe) the shower and basin also cause the cycling.

In summary the boiler seems fine with some taps but not with others - any ideas?

 

[ChrisR]

Standard symptoms, of sludge in the boiler side of the hot water heat exchanger. That will not be covered by any service/insurance company.

 

[stephenthomson10]

Thanks for the quick reply!

Couple of questions - what is the likely cause of the sludge and why does it only seem to affect the taps furthest from the boiler? Also how do if fix it!

Thanks again

 

[stephenthomson10]

Hi - anyone got any tips on this?

 

[stephenthomson10]

If anyone can help me out with understanding how sludge is causing this problem and how to fix it I'd be very grateful.

Cheers

 

[twgas]

The sludge gets stuck in the plate heat exchanger, restricting the the flow, on the boiler side, not the water side, boiler does not lose its heat quickly enough so cuts out, once it cools a bit (only takes seconds) refires and starts the cycle again.
If left, before long, all the taps will be affected

 

[StevenJames125]

some combi's may be sent to lockout with these sympstoms too

 

[stephenthomson10]

So the BG chap came last week and without delay said the HW heat exchanger had packed up. He said it wasn't covered (just as you said) and wanted £200+ for a new one. After a bit of thought we agreed and he came back to fit it today.

After a couple of hours he turned it all back on and...... exactly the same - no improvement at all. He said BG wouldn't charge as the fix didn't work so I'll make sure they don't as they make you give your credit card details before making the appointment (outrageous in my opinion).

Anyway he then said it was the main heat exchanger that was clogged up with scale and I needed a power flush at the cost of £808 to clean it out and make it work properly again.

So my question (at last) is does this sound right to you? - should I get a powerflush (probably not from BG at £808) and should I get the heat exchanger replaced as well or should I just give up and just buy a new boiler all together?