I agree, I might contact them to ask the same. I think 70-80rps max would be the sweet spot. Defrost is 80rps for me.
I find 120rps loud and can hear it through the wall. It sounds like it’s about to take off after defrost!
I know the recovery after a defrost is reduced with NR mode on but surely it’s better on the compressor as it’s not working too hard?
I posted about my Arotherm 7kW compressor noise issues (see Vaillant maximum output capacity testing - #132 by Plug1). Of course, the noise in the video is a lot louder due to the side panel being removed, but the main observation was that there was a qualitative change at higher frequencies due to resonance in the compressor assembly.
To follow up on this, a Vaillant engineer tried to fix this (under warranty) and had partial success. The slightly disappointing thing is that he started to apply quite a bit of noise-suppressing tape around the compressor before observing it running at high speeds, so did not find the root-cause of the problem. The outcome was that noise is now a lot quieter at very high speeds (90-120 rps), but there is still some noticeable resonance in the 75-90 rps which can be heard inside at certain places in my house close to the main flow and return pipes. Having seen what the Vaillant engineer did, I can probably improve this further. BTW, I find this app (https://play.google.com/store/apps/details?id=org.intoorbit.spectrum&hl=en_US&pli=1) very useful for monitoring the noise that is definitely coming from the compressor, as you can pick out the precise frequency that matches the compressor speed (e.g. 88rps will show up as a 88Hz spike in the app).
This is encouraging, thanks.
Could you possibly detail as much as you know about what exactly the Vaillant engineer did? Which type of foam tape product did he use? Some photos, and/or illustrations, would be fantastic.
It’s good that the foam tape improved it, but as the root cause has not been found I’d worry about longterm damage. That resonance is not supposed to be there and resonance can be quite destructive. I’d push for a proper fix within the warranty period.
Curious thing…my heat pump seems to be ignoring the cylinder tank temp.
My hot water is set to
Eco
48 degrees
4K cylinder charging offset (e.g. max target flow temp ~52 degrees)
Typically it will do the DHW cycle in about an hour, getting up to ~54 degree flow (eg just above set point).
However, for its past 2 DHW cycles (last night and this afternoon) the heat pump has run up to a flow temp of ~65 degrees. Sensocomfort is showing tank target temp of 48 degrees and actual temp as 59 degrees (eg it’s not that the Sensocomfort “thinks” it hadn’t reached 48 degrees, it has way overshot it).
Legionella cycle is set to off.
I did recently changed the “Max cylinder charging time” from 90 to 120 mins but in my mind this should have no impact on the heat pump’s behaviour in relation to target temperature.
Anyone had similar or has any suggestions?
Thanks as always!!!
This setting is ignored by the heat pump. You’re getting implicit charging offsets in eco and normal mode (eco = smaller offset, normal = larger offset).
As to why you suddenly see this overshoot - very weird, given that Sensocomfort picks up the correct temperature. Have you tried changing the target temperature to another value and back again. A bit of a stupid solution but nothing else comes to my mind now.
Cheers @Andre_K, I’ve just found your other posts relating to the charging offset temp. Interesting that it seems to be a completely redundant setting!
Yes I think I will try your suggestion and/or the old “off and on again”!
Anticipating summer months: I’m looking to run in ‘Expanded’ mode, so that the circulation pump is off, except during DHW cycle.
Is there a way to schedule a brief daily/weekly switch-on of the circulation pump for space heating, without actually heating? I don’t feel great about water sitting stagnant in the rad and UFH loops for 6 months…
It does that automatically. When the heating is off, once a day there’s a short pump cycle for a few seconds to prevent anything getting stuck.
Excellent, good to know, thank you!
it’s the "OT switch-off threshold: °C "
Enter the upper limit for the outdoor temperature. If the outdoor
temperature rises above the set value, the system control deactivates heating mode.
Factory setting:
– 21 °C for a conventional heat generator
– 16 °C for a heat pump
mine is on 15°C
My Arotherm respects the charging offset. Today I ran DHW during the day to test and eBUSd reported a target flow temp of 60c (hot water temp of 55c plus 5K offset). Normal mode with NR mode enabled.
Can you be sure that having NR mode enabled isn’t the cause of the 5K offset being met?
Can you repeat the experiment with a different offset value?
Which ebusd value exactly? My Hc1ActualFlowTempDesired goes to 0 during DHW. HwcFlowTemp indeed goes to Target + Offset, but this values has zero bearing on what the heat pump actually does in terms of flow rate. Does your actual flow temperature obey this during a DHW run?
ebusd_hmu_setmode_hwcflowtempdesired is the value
It reached 62c which is over slightly but it hasn’t gone below or far higher
I think this is pure coincidence. Try setting the offset to 1K, it will look the same.
I’ll set it to 10K just incase it doesn’t heat up in the 2 hour window overnight. Can it reach 65c flow? It will be on our cheap rate so I’m not bothered about COP.
Installer tried to talk me through cleaning the filter last week but I didn’t have suitable tools to undo the nut in order to remove filter. So they were here today for another job and cleared the filter and also the MagnaClean filter. Since filters cleaned earlier the flow rate went up from 12.9l/m to just 13.9l/m. It should be 20l/m.
Has anyone else experienced low flow rate that persists after cleaning filters?
Just to make sure - pump speed is on auto and Max. Rem. Head at maximum (900mbar?) and you still have the low flow rate?
