HELP: Vailiant System Boiler LOUD Vibrating Sound Whenever Upstairs Heating Is On

[Gsandhu2024]

Hi everybody,

Firstly apologises if I have posted this wrong or in the wrong section. I have a vailiant system boiler, with underfloor heating for over 2 years. I have had ongoing issues since day 1 and have now been ignored by most plumbers as they get to a point where they don’t want to sort out an issue which they haven’t installed themselves.
To cut a long story short, whenever I put the upstairs heating on I get a loud droning sound which literally shakes my floorboards from one end to the other of the house. Its so loud that literally wakes up me and the family if I set the thermostat (heatmiser) to kick in. The sound ONLY happens when I have the upstairs heating on and NEVER happens when the underfloor heating is on.

I had this issue just over a year ago and Vailiant came out. They said there was no issues with the boiler and that my system was missing an auto bypass valve? This was subseqently fitted by the corrupt plumber as his last parting gift. It worked fine for almost a year and has now returned back. The noise has been ongoing for atleast 6 weeks and feels like it is rapidly getting worse. Other plumbers have told me its the pipes rattling but I know that cannot be the case as the sound feels like its coming from the boiler but I cannot be certain, but as mentioned when the auto bypass was fitted it was fine for like a year.

Any support or help is greatly appreciated! Iv attached pictures and happy to answer as much as I can with my limited knowledge. I wanted to add a video but I can’t seem to do it?

 

[Gsandhu2024]

Vailiant Boiler Loud Drone Noise

Whenever central heating is on.

vimeo.com

I’ve managed to upload a video too

 

[ScottishGasMan]

Sounds like one or more of your thermostatic radiator valves is fitted back to front.

Next time it happens go round the radiators and turn the TRV all the way shut and all the way open, if it stops when adjusting one you've found your issue.

 

[Gsandhu2024]

Hello,

Thank you so much for your reply.

I have like 6 radiators upstairs and 5 bathroom radiators. Should I be switching them all off after I switch on the central heating? Including the bathroom rads?

 

[ScottishGasMan]

Turn heating on for upstairs and leave it till it starts making the noise.

Then go to an upstairs radiator and turn the TRV right down, if noise continues, open it back up and move to the next radiator and try again, any radiator with a TRV fitted could be causing it. If there are raidators that have old style valves that are not thermostatic valves then leave them alone.

 

[Gsandhu2024]

Hi,

The issue I have is the noise goes after like 10 seconds. I literally switch on the central heating and it then makes the drone sound for 10 seconds or so but literally vibrates the whole house.

Am I better off switching off a TRV one room at a time and then seeing how the heating reacts and if it makes a noise?

Also, would you know why the auto bypass once fitted stopped the noise for a year and then decided to come back? There also seems to be like numbers on the bypass (0.1,0.2, 03 etc) should this be set to anything in particular?

Sorry for the million questions

 

[DP]

Do as SGM says.
He knows the brand better than most.
Fully open the TRVs upstairs if you do not want to wait and then see if the noise reoccurs
If noise still there then open ALL the TRVs fully and then report back.

 

[Gsandhu2024]

Hi DP/SGM,

So iv put all the TRVs fully open to 5. All the upstairs bedroom radiators have a maximum of 5 with one of them a 6 (I’ve attached these pictures). I also have one of my bathroom radiators which have a maximum of 5.

Iv then put the central heating on and as mentioned the noise occurs for like 5/10 seconds and then switches off. The heating then works fine as normal.

This is why I asked do you suggest I switch one TRV all the way down in each room and then try to put the heating on?

Thank you again for your support

 

[Johntheo5]

If the TRV(s) isnt the problem, suggest shutting the ABV (automatic bypass) to index 6, I can't see whate its set to, 4??, the boiler itself has a internal bypass with a default setting I think on this model of 250mbar, 2.5M, its unlikely but possible that the two bypasses are fighting each other, I can never understand why its set so low, it can only be adjusted to a max of 350mbar (3.5M), I often see complaints of the Vaillants boiler return temperature being 8 to 10C higher than the actual rad returns even even with quite adequate flowrates, another one for SGM?

 

[Gsandhu2024]

Hi DP/SGM,

So iv put all the TRVs fully open to 5. All the upstairs bedroom radiators have a maximum of 5 with one of them a 6 (I’ve attached these pictures). I also have one of my bathroom radiators which have a maximum of 5.

Iv then put the central heating on and as mentioned the noise occurs for like 5/10 seconds and then switches off. The heating then works fine as normal.

This is why I asked do you suggest I switch one TRV all the way down in each room and then try to put the heating on?

Thank you again for your support

Would have helped to put the images of the TRVs sorry

 

[Gsandhu2024]

If the TRV(s) isnt the problem, suggest shutting the ABV (automatic bypass) to index 6, I can't see whate its set to, 4??, the boiler itself has a internal bypass with a default setting I think on this model of 250mbar, 2.5M, its unlikely but possible that the two bypasses are fighting each other, I can never understand why its set so low, it can only be adjusted to a max of 350mbar (3.5M), I often see complaints of the Vaillants boiler return temperature being 8 to 10C higher than the actual rad returns even even with quite adequate flowrates, another one for SGM?

Hi John

Iv attached an image below. Do you mean turning this to 0.5? It was set to 0.3

 

[Johntheo5]

That's right, screw it down to 0.5, you can always reset it.

 

[Gsandhu2024]

Hi John

Unfortunately the sound is still there.

I will need to attempt the TRV but just need some advice on how to best approach as the sound goes by the time I will get to turning down the TRV…

 

[Mister Banks]

Have you tried turning all the TRV’s off together and then seeing if the sound still happens?

 

[Johntheo5]

Maybe turn them all full on first, ie, open them fully, the start shutting them down?