Remeha Avanta - Kettling and E-7 error when running hot water

[Aristotle's Lantern]

Hi all.

Boiler's 10 years old - it's in fairly good condition but I don't think it's been serviced much (we bought the house 3 years ago)

Originally threw up an E-7 error code when running a bath.

Central heating works without a hitch. It's only when we run a hot water taps - both the up or downstairs one.

Originally I looked up the code in the manual and it's a flow/pump error, I took the boiler cover off and replaced the pump head and that didn't fix the issue - I don't know boilers, and frankly find them intimidating so at that point we decided to get an engineer in.

He's re-pressurised the expansion vessel, replaced the dhw heat exchanger and the diverter but it hasn't worked. When running hot water from the tap the valve starts fluctuating wildly and you can hear it sputtering, banging and knocking and air coming out of the valve on the top before it throws up the same E-7 error.

We got him to fit a magnaclean pro2 when he did the repair. He's put the MC3+ cleaning fluid in and we've been running the central heating through a single rad to try and shift any residue from the boiler chemically that might be built up. We did manage to run a full bath later that evening so it might be helping - but then the boiler failed again afterwards. This doesn't seem like a proper solution, we're going to keep trying for a day or so to maybe shift what's in there. The magnaclean is picking up a fair bit of sludge but frankly I'm not hopeful this is a long term solution.

I'm just asking for advice really, or for any suggestions. I'm worried we've already totted up an invoice for 600 quid with the filter/replacement parts/labour and i don't want to throw good money after bad. He said it might be the primary heat exchanger - but surely because the central heating is working fine it shouldn't be that??

Also I should say we're doing work on the house, a different plumber has moved the hot water taps upstairs and we've had a rad on and off the wall a few times over the past few months. I don't think any of this is relevant but just in case that might help any diagnosis at all?

 

[gasbanni]

I found the avanta to be a good boiler, forget the heating and filters and cleaning the heating circuit that's no the problem and it's not the primary heat exchanger.
If you've paid this chap what have you paid him for ? Just the parts he hasn't fixed the problem, I couldn't charge anyone if I hadn't fixed what I'd being called out to fix !

You've not said if you get any hot water at all. Did these problems start when the plumber worked on the taps etc ?

It really sounds like a simple fault to be honest, but it's hard to diagnose not being in front of the boiler but I don't like the sound of the chap you've got in charging all that money and not fixing the problem.

I believe Baxi bought them out try phoning them to see if you can book one of their engineers ....it might not be expensive !

 

[Aristotle's Lantern]

Thanks for your reply.

Sorry. Yes, we get hot water - sometimes it'll run for 30 seconds before the problems start and sometimes it can be a few minutes. And like i say - central heating is working fine.

The issues didn't start as soon as the bathroom plumbing was done, maybe two weeks afterwards - which is why I brought it up, enough to not be coincidence? I thought possibly some debris could have got in the pipes? but i don't see how it could get all the way into the boiler though?

We haven't paid him anything yet - before he does any more work I need to find out what he's expecting us to pay for up to this point and negotiate. I guess since he's changed parts we need to pay for those, and the installation of the filter - it's reassuring to hear you say it's not the main heat exchanger - if he wants to do that next I'll tell him not to and talk to Baxi. A flag should have gone up when he didn't really do much diagnosis to begin with - he didn't attempt to clean the existing dhw heat exchanger or diverter or anything. He just replaced them and now it hasn't worked.

 

[Aristotle's Lantern]

Update, for anyone interested or who might have a similar problem.

It *touches wood* seems to be fixed now - There's a filter on the hydroblock that engineer didn't know about, he's cleaned it and reassembled everything and the kettling has stopped.

It's annoying that we've had to pay so much money to find out it's a clogged filter but I suppose at least now we have a magnaclean and a new diverter and dhw exchanger

 

[Gasguru]

You've got a parts swapper....it takes all of a minute to determine poor heat transfer...and then it's just a systematic approach to finding the fault starting with the obvious and cheaper options.
Why did he change the diverter? Sure the spindle seal often leaks on these models but it would not normal have any bearing on an overheating boiler.
The condition of the plate can easily be determined...no need to change if it appears clean and if it does 99% can be cleaned in 15 minutes.

The filters sits in the LHS hydroblock...No. 5013 not hard to find.

https://www.heatingspareparts.com/b...anta-spc-plus-spc-eco-spc-combi-spc-28c/23281

The other suspect would be the large metal can on the LHS...it probably contains a gauze to coalesce the entrained air.

Pay him for the Magnaclean/fitting, some diagnosis time and the filter clean. The rest he can take on the chin. Why should you pay for his incompetence.
Tell him to issue a CCJ on you if he really thinks he can charge you...but there's no chance the judgement would go his way.

Have a look around the condensate pipe under the boiler...where it exits the casing is a common corrosion point...if the metalwork's holed it's new boiler time.

 

[gasbanni]

Just a slight aside the avanta is the quietest boiler I've ever come across !

One more thing there is an upgrade to the burner chamber seals and electrode, once your simple problem is solved you should should see about having this upgrade done.