excessive sludge and corrosion

[alb000000]

I have a vaillant boiler eco plus that came with a 5 year warranty.
On the last service no issues were found ( although the chamber wasn't physically opened - not required by the manufacturer as it would then require new seals)
A water sample testing came positive and was advised to have the system powerflushed.
I instructed a different firm to powerflush the whole system , boiler and radiators and inhibitor was added.
7 months later I had a fault because of a dirty ignitor. An engineer attended and found the following problems
1) cracked flue connector
2) warped flange Heat exchange
They wrote on the report that this was due to a backup on the condensed pipe.
a subsequent engineer attended and after inspection noted excessive sludge and corrosion and high turbidity of a sample of more than 1000 ppm
The manufacturer is now refusing to pay under the warranty as he claims that this is caused by something external to the boiler , he says I should turn to the firm that did the powerflushing.
They have abandoned the claim of the blocked condensed pipe as it happened in the middle of summer and the appliance would automatically shut off .
They are however sticking to the theory that the contaminated water is the cause of all the damage
Having had a long and seemingly thorough powerflush done 7 month prior it seems unlikely to me .

I would like to know whether a boiler malfunction , or the cracked flue or an overheated and warped heat exchanger could be the cause of the water contamination and the sludge and corrosion

Many thanks

 

[Scott_D]

this sounds like a right muddle if different people getting involved.
Did the installer do the servicing?
Is it some type of pay monthly insurance with a service?
Was it was shut off until the cracked flue and warped heat exchanger fixed?

 

[alb000000]

this sounds like a right muddle if different people getting involved.
Did the installer do the servicing?
Is it some type of pay monthly insurance with a service?
Was it was shut off until the cracked flue and warped heat exchanger fixed?

initial boiler was on govt replacing scheme firm no longer exist they contracted the installation to installer but he was their clients not mine
The services where carried by British Gas and then Homerserve both with whom I had annual maintenance contracts. The last service was by Homerserve ( who is associated with Vaillant ) confirms that everything was according to manufacturer instruction service . They advised me to have a system clean and I did a powerflush with a company member of the Powerflush association , however they dont seem to around anymore.
When Vaillant came for the fault, they cleaned the ignitor it and the boiler started . However following a discussion whether this call out would be chargeable if it was related to an external factor , another Vaillant engineer came and opened the chamber, he noted excessive corrosion , warped flange and said the bolier was not safe and not commercially reparable so shut it off and said I would need to replace it and would not be covered by the manufacturers warranty .
As my boiler was used and serviced according to Vaillant instructions , I am trying to claim under their 5 year warranty.

 

[Aquarius]

I'm not sure if it's worth anything but was the installer of the boiler a Vaillant approved/recommended installer? If it's overheated then yes parts can start to fail as a lot are plastic.

 

[alb000000]

I'm not sure if it's worth anything but was the installer of the boiler a Vaillant approved/recommended installer? If it's overheated then yes parts can start to fail as a lot are plastic.

But could the failure of any internal part result in contamination of the water?

 

[Scott_D]

But could the failure of any internal part result in contamination of the water?

No it would be from muck in the radiators.
Chances are the system wasn’t flushed when fitted as it would have been done as quickly as possible then onto the next.
That said the main heat exchanger shouldn’t have failed within 5 years.

 

[alb000000]

No it would be from muck in the radiators.
Chances are the system wasn’t flushed when fitted as it would have been done as quickly as possible then onto the next.
That said the main heat exchanger shouldn’t have failed within 5 years.

Thank you but I am trying to understand this .the exchanger was inspected during service on the and no corrosion was found . I was advised 2 weeks later that water came back from testing as positive. and then a powerflush was carried out on all the radiators and the boiler 10 days after that. How would the boiler be found so corroded that it is behond economical repair 6 months after that. ? Did the damage heat exchanger caused the contamination and new corrosion or the corrosion and contamination cause the damage to the heat exchanger ?

 

[SJB060685]

But could the failure of any internal part result in contamination of the water?

The formation of black or red sludge in the system is caused by oxygen in the water reacting with iron content in radiators. Theres a lot about the science of it I could rattle off but basically its down to the oxygen content within the water. Any oxygen added to the system when filling has usually depleted to levels not sufficient for prolonged corrosion within two to three months.
If you have large amounts of sludge this is a sign of air being drawn into the system, this can be caused by a few ways.

 

[alb000000]

The formation of black or red sludge in the system is caused by oxygen in the water reacting with iron content in radiators. Theres a lot about the science of it I could rattle off but basically its down to the oxygen content within the water. Any oxygen added to the system when filling has usually depleted to levels not sufficient for prolonged corrosion within two to three months.
If you have large amounts of sludge this is a sign of air being drawn into the system, this can be caused by a few ways.

the bottom line is really , should this damage be covered by my warranty and worth fighting for it , or would it be an external cause that has caused the damage .
I wonder who would need to prove this ,

 

[Scott_D]

I don’t think you have much chance.
If they are saying that sludge from your existing heating system has damaged the boiler it won’t be covered under warranty.

 

[alb000000]

I don’t think you have much chance.
If they are saying that sludge from your existing heating system has damaged the boiler it won’t be covered under warranty.

Sorry but not sure I understand, what does sludge from my system mean? If on last service there was no sludge and right after the service the entire system was powerflushed, where did the sludge appeared from? Would it not be new sludge that was created after the flush?

 

[SJB060685]

the bottom line is really , should this damage be covered by my warranty and worth fighting for it , or would it be an external cause that has caused the damage .
I wonder who would need to prove this ,

As Scott says above, if sludge has caused damage to the system then its rare that a boiler manufacturer will honor the warranty, in fact most likely impossible. Its one of the reasons systems should be flushed on installation of a new boiler.

 

[alb000000]

As Scott says above, if sludge has caused damage to the system then its rare that a boiler manufacturer will honor the warranty, in fact most likely impossible. Its one of the reasons systems should be flushed on installation of a new boiler.

I see, however I am not convinced that this was the cause of the damage. on the engineers report the cause of damage was stated as blocked condensed pipe. They never actually saw it blocked but they suggested that this would have caused the damage. They told me at the time the blockage could be the result of a frozen pipe. I am very dubious of this claim since A) it was mid July and never had prior problems B)that winter had been very mild C) Vaillant tech told me that a shutoff valve would prevent damage in case of a blockage
the issue of sludge only came later at a second inspection when they said it wasn't economical to repair it due the state of boiler

 

[SJB060685]

Sludge is caused by one thing, air ingress. The problems you mention above are not related to sludge, apart from possibly the heat exchanger. It seems to me Vaillant are doing whatever they can to avoid paying out. I cant advise further as I'm not gas qualified. God I'm glad I only worked with oil fired appliances.

 

[Scott_D]

Can you post some pictures of your boiler and the condensate pipe?
Any pictures of the paperwork they issued you?
Have you got a magnetic filter fitted?
An incorrectly terminated condensate can block or backup flooding the boiler eg if it goes into guttering.
All modern boilers are easily damaged by sludge from radiators.