Advice on leaking connection to heat exchange on Vaillant

[picklejar]

Hello everyone, I have a small leak on my Vaillant ecoTEC plus 834, it is on the connection pipe where it goes out of the heat exchange. I assume that the o-ring has deteriorated and needs replacing.

Would you kind lot be able to offer me some advice on how this is done? I would like to think I am a fairly competent person, and have fitted most of the rad and pipe work in the house, just never touched the boiler, so would like some advice first...

From looking at the maintenance manual, I plan to do the following. If you have any extra tips or I have got it wrong please can you let me know?

1. Power off
2. Close the service valves on the boiler (I have attached a picture i what I believe are the service valves.)
3. The manual mentions start test program P.06 (diverter air vent mid-position) do I need something for this, or can i skip?
4. Open the drain valve with a bucket to drain the boiler (I have maked this in the under boiler photo too, hope its right?)
5. Manual mentions to make sure the cap of the automatic air vent is open so boiler can drain fully. Is this behind the pump, and has a release cap that i can rotate, can anyone offer advice on this?
6. Remove the air intake pipe by unscrewing and pulling off
7. The leaking pipe is the one at the back (return connection i think, see picture), so i assume i will need to remove both? or do you think there is enough room to only replace the back one. Unfortunately my boiler does not allow the side panel to come out.
8. So, unclip clamps
9. Detach the flow connection. (manual just says detach, does it just pull off?)
10. Detach the return connection.
11. Clean up connections (any advice on what to use to clean?)
12. Replace o-rings coat in silicone grease.
13. Re-attach return and flow connection
14. Re-clip clamps
15. Fit air intake
16. Close drain valve
17. Open service valves
18. Power on
19. Prey it works

Sorry for the long post, just need to make sure I have it all right in my head before I start. I’m hoping to get this done on the weekend.

leak

• picklejar
• 20 Feb 2013
• 1

service valves

• picklejar
• 20 Feb 2013
• 1

 

[conbow]

does your leaking return pipe have a black rubber connection piece half way down?

 

[Bunnyman]

Ur dabbling with safety so u won't get advice on this, ur removing the combustion chamber and air inlet which are gas related, get a registered gas engineer in

 

[The831Bunny]

I'd be hoping it isn't the main heat exchanger socket that's cracked rather than the tube O ring needing replacing.

As Bunnyman says, as soon as you remove the front boiler case, you need to be Gas Safe registered. Carrying out a repair on that leaking pipework requires you to remove the air inlet pipe to gain access, which is not DIY work at all.

 

[picklejar]

does your leaking return pipe have a black rubber connection piece half way down?

Yes it does.

 

[picklejar]

Ur dabbling with safety so u won't get advice on this, ur removing the combustion chamber and air inlet which are gas related, get a registered gas engineer in

Thanks for your reply, but removing combustion chamber? I'm removing the air inlet duct.

 

[picklejar]

I'd be hoping it isn't the main heat exchanger socket that's cracked rather than the tube O ring needing replacing.

I hope not!

As Bunnyman says, as soon as you remove the front boiler case, you need to be Gas Safe registered. Carrying out a repair on that leaking pipework requires you to remove the air inlet pipe to gain access, which is not DIY work at all.

Thanks for the advice, I'll call the company that serviced the boiler.

 

[picklejar]

Gas engineer has visited for a quote, and he has agreed that it looks like the o-ring, but has advised to also replace the rubber hoses on both pipes, as work is being done there and they are a prone to burst (bad design).

Although the rubber pipes look ok he said they probably wont last as long as the boiler and if they split could cause a lot of damage on electrics etc.

He has quoted:

£120 for parts as the vailant parts are expensive
£70 for labour
£40 for service (reduced as he is there)

Would you agree on the advice and costing? a bit of googling has found that the rubber pipes do bust, just wondering how often.

 

[Bunnyman]

Blindly that's an excellent price I would snatch his hand off for that

 

[Agile]

It certainly sounds cheaper at first sight than I would be quoting.

But then I include a service in my repair price!

So my price would end up being about the same.

Tony

 

[picklejar]

That's great, thanks for putting my mind at rest.

He is booked in for later in the week. I guess as there have been no comments about replacing the rubber hoses, then it seems fair enough.

 

[Agile]

The latest solution to the rubber hoses is a mod with copper tubes!

Tony

 

[picklejar]

Boiler all fixed now.

But had a shock when he found that there was 2 hairline cracks on the black plastic part of the main heat exchanger!! So he had to replace the whole heat exchanger!!

Really losing faith with Vaillant, what with the replacement copper from rubber hoses and cracked heat exchanger.

 

[Agile]

831 did "hope" that it was not that part cracked!

Its not a problem we hear of very often so you have been rather unlucky.

Did he replace the rubber with the copper pipe modification?

Tony

 

[picklejar]

831 did "hope" that it was not that part cracked!

Its not a problem we hear of very often so you have been rather unlucky.

Did he replace the rubber with the copper pipe modification?

Tony

That's exactly what the gas engineer said, that I was very unlucky. he also shopped around and found the heat exchanger for £360, which seemed like a good price, just not an expense I was expecting.

He also replaced the rubber hoses for the copper ones, so finger crossed I should be ok for some time. Lets hope the next time i see him, it's for a service next year!