Valliant Plus 418 Heat Exhanger broken after hot water tank

[justhomeowners]

Hi there

Help!

We've had a Valliant Plus 418 boiler for just over 3 years with a service every year and no problems at all in that time.

Our plumbers have just this week replaced the old hot water tank for something more efficient but it didn't seem to be working properly after fitting with lots of banging noises coming from the pipework. The plumbers said it was just air but since the boiler started making noises like a lorry so we called them back.

They took apart the boiler and found that the heat exchanger was full of green limescale. It would seem this is why the boiler was making such a noise!

The plumbers have said that the heat exchanger will need to be replaced but won't commit to it being covered by the Valliant warranty as they said they've not seen this problem before.

I don't know how boilers and hot water tanks work but I'm thinking that it's a coincidence that the boiler should break the day after the water tank was changed. My question is what chance that the green limescale deposits made their way to the boiler from the tank while it was being removed?

I'm hoping someone will be able to give me some advice to arm myself for when the plumbers return to fix the boiler.

Many thanks in advance.

 

[Agile]

Arming yourself? Are you going to start a fight?

I would wonder if the system and tank was correctly configured before!

have you always had a feed and expansion tank? Or a pressure gauge and orange expansion vessel with filling point?

Its always difficult to guess what has happened in cases like this.

So much relies on the knowledge and integrity of the people doing the work.

I would have been happier if you had called them heating engineers rather than just plumbers! Are they even gas safe registered?

Tony

 

[justhomeowners]

Hi Tony

Thanks for your reply. Sorry for the wrong use of the term plumbers - you're correct, heating engineers would be better suited!

Our guys are fully registered etc and have done a stirling job until this surprising turn of events. I'm only 'arming' myself in knowledge to better understand how and why something like this would or could happen. I really know very little about how these systems work.

I do know that we don't have a water tank in the loft but did have what seems to be a quite complex water tank that continuously fed hot water and heated our underfloor heating. The previous tank has been replaced with a smaller tank that has two 'expansion bulbs'. It looks very clever but my concern is the timing of this being fitted and the boiler breaking.

Does that make sense?

Many thanks

 

[sooey]

Sounds like it's been drained and fired up without purging the air from the heat exchanger.
If it's still under warranty get vaillant out and see what they say.

 

[justhomeowners]

Hi there

Many thanks - could that have caused the pile of limescale type material that was found inside? I can only think that came from the tank piping?

Many thanks

 

[sooey]

Don't know, I would suspect that's muck that's been shaken out of the heat exchanger coils as it's been trying to vibrate itself off the wall.
But I'm only guessing without a pic. I do know that firing one of these up without purging it can result in a well fcked heat exchanger.
Like I said get vaillant out to it if it's still under warranty, they should be able to tell you exactly what it is and what caused it.
edit to add...nothing from the tank can get to the part of the heat exchanger which is visible when stripped.

 

[justhomeowners]

Hi - it did sound like a truck and the boiler was vibrating like mad!

I do have a photo so perhaps I'll post that and see what you think. The heating guys have ordered a new part but are being illusive about who is going to pay for it or if it's covered by the Valliant warranty. I'm guessing it won't be covered if they didn't quite get it right when fitting. I don't really want to be left with a bill for something was wasn't our mistake.

Thanks for your help so far, it's much appreciated.

 

[sooey]

Is it still under warranty?
I don't know the cost of those heat exchangers off the top of my head, 4 or 500 quidish.
I wouldn't just let them fit one and then bill you for it without knowing what's what.
Like I said in my previous post, nothing from the tank or pipework can end up in the part of the heat exchanger which you can see when the burner is removed.

 

[justhomeowners]

Hi - that's really useful knowing that nothing can get into the heat exchanger (I literally don't know a thing about all this!) and I'm not keen on them just fitting a new part without me knowing who is responsible and me getting the bill for it!

It's 3 years and 3 months old - Valliant seem to have long warranties but the heating engineers are being sketchy about why this happened so I'm trying to learn from you fine people to better understand the situation.

Let me find the photo and perhaps you can take a look later and se if it's what you're suggesting?

Thanks again

 

[Dean744PiN5]

As sooey has said, if these boilers are not purged properly of air they make an awful racket, can take a while to get them going again too with that stupid little air vent on the side of the heat exchanger, had to leave one running with a hose connected to it for half an hour once to clear it all.

 

[justhomeowners]

Hi there

They said that the system had air in and that it would take a while to work its way out. I had to release the screw on the pump next to the water tank until water trickled out and presumably air too. That pump was drawing water from the boiler and making quite a noise itself but nothing like the boiler was making before it died.

I'll post that photo when I'm home in a bit - it shows the inside of the heat exchanger (I think!) with a pile of green limescale looking material. I know nothing about all this but that must have been what killed it!?

Thanks

 

[Dean744PiN5]

needs to be purged properly from the vent at the heat exchanger, as said can take some time.

 

[justhomeowners]

Hi again

So, I've grabbed the photos that were taken of the boiler and it looks like there is green limescale looking material around the 'heating element' along with the inside of the 'drum' too. We have a water softener installed - an Aquadial. Presumably something like this would have been picked up on in a service perhaps?

Many thanks

What do you think of these images?

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• justhomeowners
• 28 Aug 2014
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• justhomeowners
• 28 Aug 2014
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[/img]

 

[MJGas]

Service every year my arse.[/url]

 

[Phill Peck]

That's not lime scale the insulation panel has disintegrated.

Where does your condense pipe go?
Rainwater pipe would be my guess
Had heavy rain recently?