Got Vaillant coming on Monday. Any tips on how to get them to sort the sensors and humming sound in the house?

Posted by: @adamk

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Got Vaillant coming on Monday. Any tips on how to get them to sort the sensors and humming sound in the house?

Sorting the sensors - get them to swap them round or put both on the same pipe to demonstrate that they are matched, otherwise they will probably put in two new equally random sensors.  Note the mismatch and which way round they go for future reference

Humming - make sure you know what triggers it so that the conditions can be created when they are present.  Otherwise sods law guarantees there will be no humming when they come.

@jamespa

They came and after a bit of push back accepted my idea to put all 4 sensors in the same place indoors and wait for them to balance. Now have 2 that are within about 100ohms of each other. Couldn’t suggest a fix for the humming other than the installer should have used Vaillant flexis. Did say the installer could move the external pipe clamps which I think might also help.

What I’ve noticed is I’ve still got the 0.2c gap which I’m guessing is the wiring resistance possibly. I’m going to cover the sensors in some insulation to see if that helps. If not I’m assuming the sensors goto the main pcb box so might measure the resistance there. Why they don’t put some small trim pots or software adjustment on these I don’t know.

I did find out today that the sensors are exactly the same as the ones used on Vaillant boilers. As that’s what he had with him. You can remove them from the boiler clip and fit them to the heat pump clips.

Posted by: @adamk

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I did find out today that the sensors are exactly the same as the ones used on Vaillant boilers. As that’s what he had with him. You can remove them from the boiler clip and fit them to the heat pump clips.

I expect they are all made in the same factory in China!

Posted by: @adamk

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What I’ve noticed is I’ve still got the 0.2c gap which I’m guessing is the wiring resistance possibly. I’m going to cover the sensors in some insulation to see if that helps. If not I’m assuming the sensors goto the main pcb box so might measure the resistance there. Why they don’t put some small trim pots or software adjustment on these I don’t know.

I suspect because the absolute value doesn't matter to the day to day operation and they don't guarantee the accuracy of energy or COP readings, which is the only thing materially dependent on them being matched!  Not entirely satisfactory I agree, it wouldn't be that difficult to calibrate them!

Posted by: @adamk

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Couldn’t suggest a fix for the humming other than the installer should have used Vaillant flexis. Did say the installer could move the external pipe clamps which I think might also help.

If there are no flexis then fitting them may well help.  If he has just used third party ones then less likely.  If you can find something that is vibrating in time with the hum that may give a clue of a point to either isolate or clamp!

@jamespa the installer did fit primary pro flexis which aren’t that flexible. Because they had to move them as they were bending them which the manufacturer said was wrong they are being held by 3 per flexi wall clamps, I think just because those clamps were already there when it was solid pipe. So I plan to remove some so the flexis have more room to flex. Might help but not sure.

Heard a rumour Vaillant are shelving the 7kw and brining out an 8kw. Wonder what the threshold is for getting our noisy units swapped.

Posted by: @adamk

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Heard a rumour Vaillant are shelving the 7kw and brining out an 8kw. Wonder what the threshold is for getting our noisy units swapped.

The 7kW is (in terms of output) what most manufacturers would call an 8kW (or even 9), so this might just be a marketing exercise.  However they are launching a new range with, I believe, a different compressor, distinguished by a fashionably black case.

Just seen the videos for the new arotherm pro. They’ve managed to get a 7kw into a 3.5/5 chassis. I’ve still got the noise issue that no one at Vaillant wants to fix it seems. Lots of finger pointing between plumber/installer/vaillant. I paid partly with a credit card and wonder if I need to start using that to pressure Vaillant via the installer?

Anyone managed to lever Vaillant to fix this issue? Surely if it’s vibrating the pipe work eventually it’s going to cause cracks in the solder joints.

Posted by: @adamk

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Anyone managed to lever Vaillant to fix this issue? Surely if it’s vibrating the pipe work eventually it’s going to cause cracks in the solder joints.

My heating developed a really severe case of noise and vibrating pipework a few days ago.  I had to turn it off it was so noisy.  Turned out to be an air lock in the primaries, absolutely nothing at all to do with the heat pump.  Fixed by shocking the system by turning isolation valves rapidly on and off while the heat pump was running.

I'm not aware of any known problem with vaillant water pumps, and a noisy compressor (with which there is a known problem at certain conditions) is relatively unlikely to cause the water pipework to vibrate much (certainly not to the extent of damaging joints), although the noise may be carried by the pipes.

Are you sure your problem has been correctly diagnosed?  

@jamespa maybe it wouldn’t damage the pipework but this is a low frequency around 60hz and I’ve seen bolts unscrew on engines with just vibration. Can feel it thought the primary pro. It only affects some 7kw units, one installer on yt in Scotland even installs them without flexis, it’s a known issue that Vaillant has chosen to ignore. Blaming in my case how the pipes are mounted and the primary pro flexis.

this thread explains it:

https://community.openenergymonitor.org/t/vaillant-arotherm-excessive-noise-from-compressor/27824

and in that thread is a sort of fix which shouldn’t be needed if Vaillant could be bothered to visit the site and take the unit apart to find the cause.

this vid shows the fudge:

https://youtu.be/m4YxHzXisGs?si=2jDGnqVoavpwP2kL

Thanks and noted.  I dont see Vaillant doing a general fix, I think they have concluded that its limited to a small subset of installs.  You will likely need to put pressure on them if you want yours looked at.

Mine is noisy at low temps when it recovers from defrost,  Thats the only time.  I run on low noise mode at night and for me that is, pragmatically, sufficient to fix the problem.  Im not sure whether I need to do this, its more a courtesy to the neighbours!