Noisy Cylinder Continuing Saga - Help Wanted!

[WSB]

I have posted this saga over the last few months, so thought I would update with the latest info and problems.

I welcome any advice and suggestions, as I'm at the end of my tether with this.

The story thus far :

Exactly 1 year ago I had my trusty Baxi Bermuda back boiler system completely replaced by Boxt. I had no choice, back boiler had finally died....

Had Worcester-Bosch Greenstar 18Ri fitted as a pressurised S plan system with Gledhill cylinder.

7 months after installation in Sept, when the hot water only demand came on, a very loud vibrating noise could be heard coming from the cylinder.

Boxt engineer diagnosed a faulty coil within the cylinder, so the cylinder was replaced. All was fine until 3 weeks later when the noise returned, exactly the same as before.

Subsequent Boxt visits changed the HW and CH zone valves, which made no difference.

Then on the advice of Gledhill tech support, a valve was put into the cylinder coil return.

This fixed the problem and I thought all was well until yesterday when the same problem has returned again (3 weeks after the valve was put into the coil return).

It's strange that after cylinder changed and coil return valve fitted, it takes about the same time for the problem to return.

Got another Boxt engineer coming out soon but thought I'd do a bit of research of my own. Hence, this post.

Spoke to Worcester-Bosch and Gledhill Tech support who advised dialling down the coil return valve a bit to reduce the flow, to stop the coil vibration.
Also, to check if it's possible to change the external Grundfos settings somehow. I believe this pump is an ERP (Energy Reduction Pump), so not possible to manually change its speed but maybe there's some other setting that on the pump that could help? Any ideas?

Anyway, thought I'd put this out to tout any suggestions.

Many thanks in advance.

Cheers!

 

[Johntheo5]

Can you post a photo of the external? Grundfos Pump while running. showing the LEDs, also show/state its model number.

OK, I see you have a internal pump.

EDIT.
it shows a external pump in the WB MIs but you stated in another thread in reply to my same query (re internal or external) that its a internal pump, can you check this out again.

 

[WSB]

Can you post a photo of the external? Grundfos Pump while running. showing the LEDs, also show/state its model number.

OK, I see you have a internal pump.

EDIT.
it shows a external pump in the WB MIs but you stated in another thread in reply to my same query (re internal or external) that its a internal pump, can you check this out again.

View attachment 408948

Hi, Very sorry for the delay in getting back to you. Your help is very much appreciated. Have attached pic of pump now. Do you know what setting it should be set to please?

 

[Johntheo5]

Just start up any zone and lokk at and post a snapshot of the LEDs. IF its running with one solid green followed immediately by two solid yellow LEDs then its running at full speed which can lead to excessive noise, while its running, just press the setting button briefly to change settings, suggest constant curve 1, just one solid green LED and see if that makes any difference.

 

[WSB]

Just start up any zone and lokk at and post a snapshot of the LEDs. IF its running with one solid green followed immediately by two solid yellow LEDs then its running at full speed which can lead to excessive noise, while its running, just press the setting button briefly to change settings, suggest constant curve 1, just one solid green LED and see if that makes any difference.

View attachment 409719

Many thanks, will do. Much appreciated!