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Icos 24HE- Heat Exchanger in situ "flush"- Proposed process- Advice wanted

Discussion in 'Plumbing and Central Heating' started by ohitsaidwalker, 4 Dec 2018.

  1. ohitsaidwalker


    4 Dec 2018
    Thanks Received:
    United Kingdom
    Hello all.
    I have the above condensing boiler-which makes a very loud banging/kettling noise initially on start up for 10 minutes or so.. then seem to settle- quiet.. and then periodically the noise returns without there being a regular pattern to the noise that I can identify, but it is quite disturbing. I've introduced a number of Fernox and Sentinel "cleaning" products into the system. I've also mains flushed the system and I thought initially it had improved, but the noise has returned albeit perhaps marginally better?
    The noise/banging/popping reverberates throughout the central heating system but is definitely sourced to the boiler.
    I am of the view that the root cause for the noise is that the heat exchanger is calcified.
    I was pondering the below process and would welcome your views.
    I plan to :
    1-Drain the central heating system down.
    2- (see Picture) Directly above the boiler break into the 22mm feed and return pipes- I fitted a Fernox T1 Filter to the return pipe and so can use that as point of access, and on the feed side break in below the drain off point.
    3-Using a submersible pump introduce on a flow and return basis via the 22mm pipe(stepped down to 15mm and standard hosepipes) a chemical agent such that it circulates directly through the boiler/heat exchanger- and allow to flow through the boiler/heat exchanger on a continual basis for x period of time
    *Does this proposal make sense- am I on a reasonable logic path? Are here any obvious challenges?
    *What agent could I use: Fernox DS3, Fernox DS40, White Vinegar, On You tube videos where the exchanger has been removed I've seen 'One Shot' drain cleaner and 'Liquid Power House Spirits of Salts'(But these are highly corrosive as I understand and Id sooner not)
    * What pump could I use, a low flow rate ie just to circulate the agent/solution or something of a higher pressure to force out the calcification.
    * Would a system power flush deliver the same benefit?

    I am a reasonably competent DIY'er but clearly do not want to compromise any gas or boiler safety regulations, but given I am only tending to the water side believe that I am not in breach of?

    Thanks for any thoughts you may have.

    Attached Files:

    Last edited: 4 Dec 2018
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