What is this material in my Heat exchanger

Main Eco Compact boiler installed 18 month ago, system power flushed immediately before and straight after boiler installation, Magfilter 2 and inline descaler installed at same time.

Boiler has just failed with blocked plate heat exchanger on the DHW side, heat exchanger cleaned and everything is working ok now.

Note: The heat exchanger was blocked on the DHW side only, with what initially looked like flakes of plastic (I managed to kept a small piece for examination see photo) as though something in the boiler is breaking up, but on further examination it appears that these flakes are not plastic at all but rather some sort of particulate composite material for want of a better description which I can pickup with a magnet therefore contain metal

My question is of course where did this material come from?

1. Does my drinking water contain these particles (i.e am I drinking this stiff)?
If my understanding is correct, cold water comes directly into the boiler unfiltered, is diverted through the heat exchanger then straight out to the hot water/mixer tap? Therefore there should be no difference between the hot and cold water as far as the actual water content or any deposits it may contain.

2. If the particles are just in the water but so small that they are not visible to the naked eye in a glass of water then why has it accumulated in my Heat Exchanger and formed this composite material that looks like pieces of plastic?

3. Why does some of it look like it is shaped the way it is (how did it get this shape)

4. Could it be the inline descaler we installed causing this as it is the only thing that has changed on the cold water side since the boiler we replaced?

No picture ?

ShaunCorbs said:

No picture ?

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Hi thanks for your reply I couldn’t figure out how to upload these picture

I would ask the person who did the system flush back again as it doesn’t look like maybe he flushed it good enough

ShaunCorbs said:

I would ask the person who did the system flush back again as it doesn’t look like maybe he flu

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ShaunCorbs said:

I would ask the person who did the system flush back again as it doesn’t look like maybe he flushed it good enough

Click to expand...

Thanks for your reply much appreciated, but as I stated this material is only present in the DHW side of the plate heat exchanger, now in my mind (and I’m more than happy to be corrected) cold water supply goes directly into the plate heat exchanger and comes directly out of the plate heat exchanger to my mixer tap therefor actually doesn’t go through any other part of the boiler, it seems a system flush would have no effect at all, or put another way no matter how good the original system flushes were this material would still accumulate as it is being collected from the cold water supply not the Central heating system.

But my question was, where is this material coming from?

It seems like no matter how many times I have the heat exchanger replaced this problem will reoccur unless I can figure our where it is coming from, which has led m3 to suspect the inline descaler which is fitted to the cold water supply before the boiler.

Any comments or opinions appreciated

As it’s metallic are you 100% sure it came out of the cold side and not the heating side

ShaunCorbs said:

As it’s metallic are you 100% sure it came out of the cold side and not the heating side

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Yep as you can see the left (or top when installed) is the DHW which is completely blocked and the right port in the picture (or bottom) is the central heating chamber which was completely clear when they ran water through it.

That’s the heating side if the writing is readable and it’s the top port

ShaunCorbs said:

That’s the heating side if the writing is readable and it’s the top port

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It is the top port for sure and that now makes absolute sense to me, it also means the bloke who replaced it told me incorrectly that the top/blocked port was the DHW side.

Thank you for your prompt assistance, it’s very much appreciated

I don't know the boiler / heat exchanger but to me it seems like the Hex has been re fitted the wrong way around, if that's possible, so that deposits previously built up on the heating side are now washing out in the Domestic hot water.

An inline descaler on the mains cold water wouldn't have any effect on deposits building up on the heating side, which those deposits appear to be.

snowhead said:

I don't know the boiler / heat exchanger but to me it seems like the Hex has been re fitted the wrong way around, if that's possible, so that deposits previously built up on the heating side are now washing out in the Domestic hot water.

An inline descaler on the mains cold water wouldn't have any effect on deposits building up on the heating side, which those deposits appear to be.

Click to expand...

Thanks for your reply

snowhead said:

I don't know the boiler / heat exchanger but to me it seems like the Hex has been re fitted the wrong way around, if that's possible, so that deposits previously built up on the heating side are now washing out in the Domestic hot water.

An inline descaler on the mains cold water wouldn't have any effect on deposits building up on the heating side, which those deposits appear to be.

Click to expand...

Thanks for your reply it seems like I have misunderstood which side is primarily, thanks to Shauncorbs for pointing out my mistake, still not sure why the plate heat exchanger became blocked so soon but at least I know I’m not drinking this stuff which was my concern

It’s the first to clog due to the small waterways etc