Second Opinion on Vaillant Boiler Leak

Hi all,

I am after a second opinion on a boiler leak that first manifested itself as drips coming from 2 or 3 different places underneath the boiler.

It is a Vaillant Home Combi 35 that was fitted in 2016 in a new build home.

I removed the front cover to try to pinpoint exactly where the leak is coming from and it appears to accumulate in the location highlighted by the green arrow in this photo:

https://1drv.ms/u/s!Aug4dcHmOxGZpS3L3UNCudGXGoXp

It then drips/runs down and collects on the bottom where it then escapes in a few different locations.

A gas safe engineer was sourced and visited the property and on a very quick inspection he determined that the heat exchanger was leaking and that the boiler would need to be replaced at a cost of ~£2k.
He did not entertain the idea of repairing it or replacing the faulty heat exchanger.

I am hoping someone with knowledge of boilers on here could look and see from the photo whether they agree with the diagnosis of a leaking heat exchanger, but also whether it would be a viable repair on a boiler of this age. It is out of warranty as Persimmon only provided a 2 year warranty with these boilers (unbelievable, I know).

I have seen on parts distributors online that a heat exchanger for this model can be procured for about £350 so surely the entire boiler is not a write off?

I would like to point out that I have no intention of interfering with the boiler myself as I understand the principal of 'a little knowledge is a dangerous thing'. Beyond taking the cover off to try and pinpoint the source of the leak, you can rest assured I am not willing to fiddle with it.

Any advice greatly appreciated.

you need a new sump

Gigagator had a problem and wrote 304 words and the answer came back in 5.

Well done Ian.

Andy

1754 characters if anyone was wondering.

Andy

Theres a 95% chance it doesnt even need the heat exchanger. The sump, if required is available on its own, And chances are its actually a flue seal further up which is dripping down to look like its the heat exchanger. Get a competent engineer in that owns an inspection mirror and will spend more than 30 seconds before trying to sell you a new boiler.

Gigagator said:

as Persimmon only provided a 2 year warranty with these boilers

Click to expand...

Keeps the cost of the boiler low.

Hi all,
Massive thanks for the prompt replies.

When you refer to the sump, is it this part:

Vaillant Part No: 0020195478 | Condensate drain | 24 Hour Delivery | Heating Spare Parts

Vaillant 0020195478 Condensate Drain (warmsafeplumbingandheating.co.uk)

To reiterate, I am not interested in purchasing the part myself and 'having a go', it's just for my own information and understanding.

My usual and preferred engineer for this sort of work is currently unavailable as he is rammed with contract work for British Gas so I am having to put trust in tradesmen I don't know and it's not been a great experience so far!

We have had another engineer out who spent more time looking at it and he did say 'I don't think it is the heat exchanger' but didn't seem particularly interested in taking on the work, for some reason.
He suggested contacting Vaillant who have a one off repair cost of £311, which now seems excessive if the heat exchanger doesn't need replacing.

yes that part is the sump,but they are not all the same so make sure you get the correct one for your boiler

Just wanted to follow this up with what became of it.
The owner of this boiler (a neighbour) ended up going through their insurance and a Vaillant engineer was sent out.

He did not replace the sump but instead replaced the flue pipe, which I understand is the black plastic pipe part that attaches to the sump.

So far no leaks but will keep an eye on it and update this thread if there are any further developments.

Gigagator said:

He did not replace the sump but instead replaced the flue pipe, which I understand is the black plastic pipe part that attaches to the sump.

Click to expand...

nope that is not the flue pipe , that is the sump, the flue pipe is white and goes out through the outside wall

That was my understanding too.

I was just going off the part list name from here, as this is what he replaced: Vaillant Part No: 0020195475 | Flue pipe | 24 Hour Delivery | Heating Spare Parts



Anyway, fingers crossed we are leak free now, and thank you for advice as it steered things away from a completely new boiler as the first engineer recommended.