Heat Exchanger Split + Power Flush

[nojo901]

Hi
I have a 3.5 year old Keston Q28S combi boiler on a pressurised system that has been losing pressure for some time.
BG have finally diagnosed a split heat exchanger that they are replacing under contract.
They say that this is due to "aggressive (!) water" and that they will not cover further work due to sludge, unless I have a power flush.
I do accept that several of my rads are cool at their bases.
BG have quoted an absurd figure for the flush and the guy was good enough to agree that I should go elsewhere for this (I know the "BG Power Flush saga" already!).
A couple of questions, please:
1) Would a heat exchanger split for this reason?
2) In this instance, does it make sense to have a flush (after the replacement is conducted) - I already have a BG filter on the system?
3) Has anyone heard of Expert Powerflush - they have given me a good quote in the past
Thanks

 

[HITGAS]

Heat exchangers are more likely to split because of sludge. You will notice sludge in a combi because the water water will have problems as the plate heat exchanger blocks with sludge.
It makes sense to flush the system removing the aggressive water. Sludge and combis don't mix. Get a flush asap, remove all the sludge, if after that some rads still have cold spots change the rads.

 

[DP]

Radiator cold at the bottom means inadequate circulation. A better option would be to check inlet/ outlet temperatrures- this will indicate how good or bad the flow through each radiator is.

Only yesterday attended a system that was to be flushed similarly by such a mob. Turned out to be out of balance system

Keston HE bursting- search these pages. I think it is quite common.

 

[45yearsagasman]

Aggressive water will also pin hole your rads and will not be covered as you have been advised to clean the system. This advice will have been recorded.

 

[nojo901]

Thanks. I assume that re. The cover, I do not have to have BG do the flush?I.e its OK if I have another plumber do it and give me written confirmation that he has?

 

[mickyg]

Kestons do not need aggressive water to start leaking. Your average bog standard water will make a Keston leak quite well
How do they know its sludge? Have they tested the water? taken a sample?
OR was it a guess? as is usually the case