Plate Heat Exchanger keeps failing

dk3

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Hi, just looking to inform myself before escalating issue with either Valliant or plumber. Had extension finished in Dec 2018, new pipes throughout to shower/taps/radiators. New Valliant boiler installed. Water wasn't heating fully from the off, had Valliant out Jan 19, replaced heat exchanger and all fine. Same thing in Jan 20, boiler serviced in Dec 19 and hard water filter replaced. Had Valliant out in Jan 20, replaced heat exchanger as it had scaled over. Had them out again this week as water temp dipped and they had to replace exchanger again. No charge anytime but mentioned there could be if keeps happening. Assuming the filter is doing its job is there any other issue that could be causing this. Do I have grounds for a new boiler? Its the 3rd new exchanger in just over a year in anew boiler. Many thanks for any help.
 
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Sounds like your scale protection isn't up to the job. Can't see how this can be a boiler issue.
 
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dk3

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Hi Muggles, I have been assured it was by the plumber. Many thanks for your reply, I don't know enough about it and want to make sure I go the right path to resolution.
 
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dk3

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The scale protection is Combicare scale inhibitor by BWT. Is that a decent product?
 

dk3

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Thanks Bob, was changed in Dec as part of first annual service. Maybe a faulty one fitted or badly fitted and resulted in plate issue 7/8 weeks later?
 
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The scale protection is Combicare scale inhibitor by BWT. Is that a decent product?
No, they're utterly awful and well known for blocking up heat exchangers - this is very likely to be your problem rather than scale. Having nothing at all would be better than having one of those. Get it taken out and get a Hydroflow HS38 instead. Buy cheap, buy twice ;) but make sure you RTFM before you fit it!
 
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No, they're utterly awful and well known for blocking up heat exchangers - this is very likely to be your problem rather than scale. Having nothing at all would be better than having one of those. Get it taken out and get a Hydroflow HS38 instead. Buy cheap, buy twice ;) but make sure you RTFM before you fit it!

Do any of these things do anything at all? Aren’t they rather pseduo-science?
The Hydroflow claims:

“is a piece of equipment which fits around pipework and transmits an electronic signal into the water contained within. The signal propagates around the entire pipe system and causes the limescale present in the water to form into loose clusters. When the water is heated these clusters form crystals in suspension in the water which normally wash away with the flow, so that they no longer adhere to the inside of the pipework or to any other surfaces.”
 
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Do any of these things do anything at all? Aren’t they rather pseduo-science?
The Hydroflow claims:

“is a piece of equipment which fits around pipework and transmits an electronic signal into the water contained within. The signal propagates around the entire pipe system and causes the limescale present in the water to form into loose clusters. When the water is heated these clusters form crystals in suspension in the water which normally wash away with the flow, so that they no longer adhere to the inside of the pipework or to any other surfaces.”

I used to think the Hydroflow HS38 was utter nonsense until I saw the results myself. Some of their marketing photos are my photos. I took out two cylinders of almost identical age (approx 15 years old) last year. They were at two different jobs a few miles apart, off the same hard water supply, fitted to similar systems running at similar temperatures. The two installations were as identical as anyone could hope for in the real world.

The differences? One was absolutely full of scale, about a third full in the bottom of the cylinder. The other was spotless, save for a light green sheen on the coil. The one full of scale had no protection, the clean one had a HS38 fitted to the cold feed. I don't quite understand how they work, but I'm now completely convinced that they do
 
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You have been fortunate that the boiler manufacturer has replaced these under warranty, as it is not a boiler fault, they will not keep doing this, your scale protection is to blame not the boiler
 
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I’ve been told they work by taking the rough edges off the limes ale and making them smooth so they can’t stick to anything,if that makes any sense
Bob
 

dk3

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No, they're utterly awful and well known for blocking up heat exchangers - this is very likely to be your problem rather than scale. Having nothing at all would be better than having one of those. Get it taken out and get a Hydroflow HS38 instead. Buy cheap, buy twice ;) but make sure you RTFM before you fit it!

Hi Muggles, can I ask how Combicare product would contribute to the problem. Plumber and Valliant both been out. Plumber says it's a good product and has never had an issue. Valliant says it's not a boiler issue and he has worked the area for years and it's not a common issue. Previous boiler was fine, also Valliant, came with the house, didn't have a filter on it.
 
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The granules escape from the canister and get washed into the boiler. They stop where they can't get through
 

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