EvoHome, Vaillant Exclusive and radiator noise

[MilkDawg]

Hi

I have a Vaillant Exclusive 832, which feeds 7 radiators in my bungalow. I have an issue with radiators making like a whistling noise when the heating comes on in that room (I use EvoHome so only one or two rads are normally on at one time).

When the boiler was installed, it was not configured at all, they put it in and scarpered (about 5 years ago now, before I fitted EvoHome too). About two years ago I looked into it as our gas was much much higher than before and noticed that the output had been left on max, so I reduced this down to the lowest setting which I think was 8KW.

Now I am thinking that due to the whistling noise, should they have configured the pump speed or auto bypass? It does sound like the pump is too high but I am no expert in boilers.

There is one rad that doesn't have a TRV fitted, that is a large towel rail in the bathroom.

I have looked at the manual which states "If noises are produced in the radiators or radiator valves" then "Regulate the pressure using the adjusting screw" by "Positioning the adjusting screw" to "5 further turns to the left from the mid-position". Does that sound like what I need to do?

Any help would be greatly appreciated.

 

[cross thread]

by pass or possibly the locksheild valves want opening more

 

[MeldrewsMate]

I suggest that the largest radiator in the house should have it's lockshield fully open, the pump speed then adjusted (I am not familiar with Vaillant, but have seen some where the max pump speed can be adjusted in settings) to the lowest speed that will give the correct temperature difference across the boiler at full output, in your case only 8kW (maybe 18kW?). Then adjust the lockshield on the second largest rad to give a similar temperature drop, and so on for the other four. The bathroom rad will normally have the lockshield valve only about a half turn open for a towel warmer.
Once that is done you may need to increase the pump speed a little to get all rads to full temperature.
At the end you should find that all the rads warm up at the same rate, and all get hot around the same time, before the Honeywell system starts to mess with the TRV settings.
Once done you may well need to adjust the Vaillant Bypass Valve if the noise persists, but IMO if more than a couple of years old they will often leak once adjusted.
Is the TRV on the noisy radiator on the hot (flow) end of the rad?

You can see that this is a slow and methodical approach, best done over several days and weeks to get it right, and clearly would be very expensive for a pro to spend time doing it; and that's why pros use their skill and experience to estimate settings that may be less than optimum, but adequate for your needs...and some just scarper, leaving the TRVs to compensate for the other failings.

 

[MilkDawg]

Thanks for the info, I will take a look. The noise is on the flow side.