Noisy auto-bypass (rushing noise)

[ironsidebod]

Evening all,

Bit of an update on this, based on previous posts this is what I've done:

- Mains flush with X800
- Confirmed bypass pipe feeds into return
- Replaced ABV with a Myson version (doesn't rattle and will close off flow totally for balancing which wasn't possible with the Honeywell)
- Balanced radiators
- Dosed with X100

System appears to be clean, cold feed isn't blocked. Tank was cleaned etc Radiators are ~11 degrees, system temp drop is ~11 degrees with pump on speed 2.

With the boiler stat set to max for balancing there is a bit of noise once the water gets hot but it stays constant whether flow temp is 60 or 80.

However, once re-introducing the ABV and the valve closes there is a very loud kettling/water rushing noise through the system. I've done the screwdriver test at the boiler and it can be heard clearly in both flow and return pipes, at the ABV the noise is there but I think the noise is travelling along the pipes from the boiler. Main thing here is the ABV is much better and doesn't appear to be causing noise itself like the old one.

If I run the system up to temp with the ABV closed and the hot water on there is no real noise from the boiler full stop, if the hot water is on when the CH valve closes again no rushing noise.

It's very annoying as the system gets hotter quicker than it ever has and all radiators are fully hot. Any ideas before I have to get someone in.

Thanks

 

[JBF]

Did you ever resolve this completely? I have a similar issue, with a Honeywell DU144 too so it's interesting that others seem to think they are noisy valves.

I partially re-plumbed my system as the previous configuration was incorrect - it had 6 zones (totally excess to requirements) and was wired up incorrectly, so no overrun could occur (as the pump was not wired in to the boiler. I removed all the zones and converted to a standard S-Plan setup. Because the pipe run in to the airing cupboard doesn't meet the minimum bypass circuit length I used the DU144 to bypass the CH valve - so any overrun would simply pass around the CH circuit (bathroom and hall both have no TRV so are always open).

As a whole the system works a lot better but I have notice the same noise you mention when the pump is in overrun. It's very annoying. You can't actually hear it in the airing cupboard (where the valve is) but I can hear it in the living room below. Pump is on Speed 1. If I manually open the CH valve when the pump is overrunning the noise disappears so I'm certain the ABV is causing the sound.

Based on your comments I may buy a myson valve to swap in place.

 

[ironsidebod]

Hi,

Sorry I missed the topic.

I did resolve the issue after lots of research. End up having the system power flushed which sorted out most of noise from the system and boiler in general.

The final piece of the jigsaw which resolved the last bit of noise and got the behaviour right was to remove the DU144 and replace with a myson bypass. The system had behaved nicely ever since and we have virtually no noise.