Vaillant EcoTec Plus 24 - very loud buzzing

[techno12]

Hi.

I had a Vaillant EcoTec Plus 24 installed back in September 2015, and recently it's started making an incredibly loud deep bass humming/buzzing sound that literally shakes the whole flat. I initially thought it was upstairs neighbours drilling into the masonry - it's that loud!

https://www.dropbox.com/s/7c23u5zjfuja5lr/NoisyBoiler01.mp4?dl=0

I've only used the CH around 10 times due to the mild winter, and it's made this sound on 3 occasions now - normally after the heating has been on for 2 or 3 hours.

I had my system powerflushed, and there's a MagnaClean device installed. I know he added inhibitor too. System pressure is 1.2 bar cold and to 2.0 when the noise begins.

As I said, I've only run it a few times so it's effectively a new boiler...

Any ideas?

Cheers!
Tony

 

[PrenticeBoyofDerry]

If you turn the hot water on, when the noise is happening. Does the noise continue or stop?

 

[simond]

I expect it is a thermostatic rad valve.

 

[techno12]

Thanks for your replies so far - I'll try switching on the hot water next time the noise occurs and see what happens.

Regarding "thermostatic rad valve", I had them added as part of the install as my existing rads didn't have any. They're Honeywell ones and set at a mixture of either 5 or 1-2. The large rad in the lounge doesn't have one, as this is where the Nest thermostat is sited. How could these cause the boiler to make that incredibly loud sound?

Cheers!

 

[techno12]

I've turned the 2 TRVs that were set to 1-2 to 5 today, and after 4 hours' use the boiler has been fine - as silent as ever.

It does defeat the object of having them though, ie if I actually use them to suppress the heat in the rooms that I don't use often then the boiler goes ballistic after a few hours.

Guess I'll need to do some more tests to see if it's definitely those TRVs causing it (as it's possibly an intermittent fault and might not have happened today anyway, regardless of the TRV settings), and then to work out how to fix it.

 

[Agile]

Sounds like another who is relying on the boiler to provide the auto bypass.

Tony

 

[techno12]

Sounds like another who is relying on the boiler to provide the auto bypass.

Tony

Thanks for the reply.

What does that mean for an end-user like me?

I thought that so long as one rad has no TRV then you can set the others to whatever values you want for per-room fine control. The stat is in the same room as the non-TRV rad (which is by far the largest in the house, and annoyingly was the last to heat up once the Vaillant was installed, so I've attempted to balance the system by reducing the flow to some of the others via the lockshield valve and indeed the large rad heats up around the same time as the other now)

 

[simond]

ecoTEC Plus has an inbuilt auto bypass - and it can be relied upon.

 

[hertsboilers]

Might be by an offset setting for fan. Need call a Vaillant service engineer.

 

[TCCHeating]

ecoTEC Plus has an inbuilt auto bypass - and it can be relied upon.

+1 one of the few boilers that have a proper 15mm adjustable auto bypass

 

[techno12]

Thanks for the replies - rather than second guess I'll give Vaillant a call tomorrow.

I'll post back the results, as it may be useful for other people who are googling "Vaillant loud humming" etc. The only reference I could find was this

which is a very similar sound to mine, but modulates where as mine is more constant (and the poster of that vid never said what the cause was in the end - though the 'too high pressure' might have had something to do with it in his case!)

 

[simond]

Vaillant will try and stiff you for £94 to come out, refundable if it is the boiler at fault.

Are all the TRVs Honeywell, new, and all from a reputable source? EG: not eBay?

 

[Bunnyman]

Wheres my post gone then????

 

[TCCHeating]

Wheres my post gone then????

That's what I was just thinking!

Think the mods must have taken a dislike to the friendly banter with Tony

 

[Bunnyman]

Now at leastwe know agiles a mod ffs