alpha he25 whistling and juddering

[Steve.H]

Hi all, any advice would be greatly appreciated.
Customer has an Alpha he25, boiler fires and after about 2 minutes it starts whistling/humming and the noise increases, it happens when calling for heating or hot water, when the boiler shuts down it also judders for a second or 2, they sent me a video playing the sound but not sure how to put that up on here.
The system has been powerflushed recently!
Just wondering if any one has any ideas?
Going to call later today/tonight
Many thanks.

 

[Matt0029]

Could it be pump related? Maintain quiet a few of this type of boiler were I work.

 

[sammathias]

Overheating/kettling?

 

[Steve.H]

I didn’t managed to get there Friday, been thinking about it all weekend, was thinking it might be the pump but and will check it tomorrow night,(can’t go in the days due to them working during the days),
Does anyone know how to put a video up?

 

[Steve.H]

It doesn’t sound like an over heating or Kettling noise, will post more about it after I’ve been there tomorrow night.

 

[Steve.H]

Could it be pump related? Maintain quiet a few of this type of boiler were I work.

Went there tonight and it was the pump, took the pump off and could feel the pump wasn’t spinning freely, felt like grit in it catching when it spun, cleaned it out put it back and all nice and quiet with no juddering when boiler turns off!
The sound it was making was really loud more of a humming noise but didn’t seem to come from the pump, think it was resonating through the pipework in the boiler,
Thanks for all advice given, much appreciated.

 

[Matt0029]

Did you risk the isolation valve under the boiler or drain the system to take the pump out? I have found the isolation valves on alphas terrible, leak alot when turned off.

 

[Steve.H]

Did you risk the isolation valve under the boiler or drain the system to take the pump out? I have found the isolation valves on alphas terrible, leak alot when turned off.

I drained down from under the boiler, bit of a fiddle to get at, filled back up and all ok! Didn’t realise there was an issue with them, might think twice next time.