Boiler "surging"

[Jozza66]

Hi,

We've had our system working for just over a month:-

20 Rads - 18 with HR92/91
Woscester 30i System Boiler
Y Plan
Stored Hot Water

Everythign working as it should be, however we do notice the boiler "pulsing" or "surging" when the system is calling for heating. Pre the EvoHome setup when the boiler was running we'd have a constant and stable amount of noise/running sound from the boiler.

I get that having multiple rad valves in different states of opening will introduce pressure differentials into the system, but is there anything to be concerned regarding the boiler running speed/anything I need to do?

Thanks

John

[Richard]

John, please confirm you have an ABV fitted? Do you have HR92's on all radiators?

[Jozza66]

Hi, Sorry for the delayed response!

We have a plumbed towel rail, and one other radiator with no TRV installed. Every other rad has either an HR92 or HR91 installed.

There's no evidence of a bypass valve that I can see however - the cylinder is in an airing cupboard, and I can't see anything acting as a bypass on the return pipework up there. Anywhere else I might look?

Thanks

John