Worcester Bosch Boiler issue - loud shudder/vibration when boiler ignites

[aspiringtoDIY]

Hello,

I recently woke to find my Worcester Bosch 11-35 HE Plus Combi boiler had cut off with a EA fault - no flame detected. I noticed the pressure had fallen so topped up the CH circuit and restarted the boiler.

Now everytime I start the boiler it initially works, then some time later the fan gets much louder and eventually the boiler sounds as though the water inside it is at the point of boiling. It sounds similar to a kettle just before the kettle clicks off. Worse than this, when the boiler ignites there is a loud sustained shudder/vibration. This will eventually become more sustained until the boiler will cut-off with the same EA warning message.

I've had a corgi qualified plumber look at it for an hour and confirmed that it was safe, but during the hour the vibration hadn't started. He said that the fan was on it's last legs (having heard a whistling which he attributed to the bearings) and would need replacing in the near future. He also bled the boiler pump.

I've recorded the more alarming vibration and would appreciate another qualified opinion that this is indeed the problem - it seems rather extreme for a fan being faulty. How much would would a fair price be for the fan replacement?

YouTube - boilerissue
The sound on this clip doesn't pick up the vibration that well.

nb. despite the username please be assured I'm not going to tamper with the boiler!

 

[Masood]

Sounds to me like the system is full of sludge. When this happens the boiler over-pressurises and makes kettling noises like you describe. It also dumps water out of the pressure relief valve, hence it being low on water when you discovered it. The expansion vessel may also have been damaged, although that is less common..

Nothing in your description sounds like a fan issue to me. Have the system thoroughly powerflushed and take it from there. Where are you based?

 

[PlumbBobBob]

this thread is 18 months old

 

[Masood]

Oops! So it is! It was no. 3 or 4 on the thread list this morning, though!

 

[Mickyplumb]

Hello,

I recently woke to find my Worcester Bosch 11-35 HE Plus Combi boiler had cut off with a EA fault - no flame detected. I noticed the pressure had fallen so topped up the CH circuit and restarted the boiler.

Now everytime I start the boiler it initially works, then some time later the fan gets much louder and eventually the boiler sounds as though the water inside it is at the point of boiling. It sounds similar to a kettle just before the kettle clicks off. Worse than this, when the boiler ignites there is a loud sustained shudder/vibration. This will eventually become more sustained until the boiler will cut-off with the same EA warning message.

I've had a corgi qualified plumber look at it for an hour and confirmed that it was safe, but during the hour the vibration hadn't started. He said that the fan was on it's last legs (having heard a whistling which he attributed to the bearings) and would need replacing in the near future. He also bled the boiler pump.

I've recorded the more alarming vibration and would appreciate another qualified opinion that this is indeed the problem - it seems rather extreme for a fan being faulty. How much would would a fair price be for the fan replacement?

YouTube - boilerissue
The sound on this clip doesn't pick up the vibration that well.

nb. despite the username please be assured I'm not going to tamper with the boiler!

I've had this. It was an undergassed problem. The burner was battling to stay alight when it ramped up. Terrible noise. In the end, this problem was traced back to water in the gas supply but it was easily tracked as inlet pressure dropped to 16mb when it ramped up, not very forgiving those Worcesters !