Vaillant ecotech plus combi no hot water

[Fallingdown]

Hi all this is my first post on the forum, although I've managed to get quite a few answers from you all already by searching through different threads (thanks all) but i'm a bit stuck at the mo.
I'm having a problem with a vaillant ecotech 831,there was no hot water but the ch was fine Ive changed the diverter valve and got it working for about 2 weeks but the customer just phoned to tell me it's stopped again. When the boiler was going through the start up sequence there was a noise that sounded like a gear slipping that was coming from the diverter valve area which i thought might have been the actuator not working but after replacing the diverter itstill made the noise on start up, but i left there with the boiler working.
I'm not really that experienced on vaillant boilers and I'm hoping to go on the course this year but any advice would be appreciated. When I replaced the diverter valve I took off the plate heat exchanger and cleaned it through I also drained down the system and flushed out best I could with the filler loop (haven't got a power flusher) until it ran clear I didn't put any inhibiter in as I wanted to make sure it was fully working before I added any (glad I didn't I don't think I can afford to spend any more on this job) I'm going back on Monday as cust is away any advice would be gratefully recieved.
Thanks

 

[sooey]

It sounds like the heat exchanger blocked. The ecotecs all make that noise on start up as the diverter moves in and out.

 

[petertheplumber12]

If the system had sludge in it when you drained it to clear it then you cant just flush the secondary heat exchanger to clean it, It will need replacing and suggest to them that they get you to fit a magnaclene on the return pipe to protect the heat exchanger. They cost about £90 and about £40 to fit.

 

[Fallingdown]

Thanks for the help fellas especially for the advice about the noise ( put my mind to rest ) I really need to stop telling customers " it's fixed ! " and start telling them " I think that should do it maybe " at least till I get a bit more knowledge. Cheers again fellas 😕

 

[Deleted member 63160]

you cant just flush the secondary heat exchanger to clean it, It will need replacing................ and about £40 to fit.

Clearly a man at the top of his game

 

[Agile]

Nor does he realise that the OP is indeed a struggling plumber working on a customer's boiler!

One wonders why he does not post in the CC.

 

[Fallingdown]

I would have posted this in the cc but after submitting my gas safe reg and licence no and have yet to get a reply allowing me access to that forum, and after reading a few threads I noticed that you could ask and answer questions about boilers and ch in this forum as long as you don't ask or answer about gas or flueing problems, and was hoping to get a bit of advice before going back to the job. In the future I will post any boiler related questions in the combustion chamber. Thanks for the help and advice.