Combi install do I need an external ABV?

[Ironman2024]

Hi all,

I have an ideal logic Combi max2 30kwh that was installed in my hose prior to buying it.

It feeds 11 radiators in total, they are all type 22 and replaced at time of boiler I think.

1600x500 X 2
1800 x 500
1200x500 x3
1000x500
700x500
500x500 x3

There is one bypass road which is a 500x500 and the rest have TRVs

The issue I’m having is radiators upstairs close to the boiler all hiss, no matter what is done. It’s less so with fully open trv.

I can live with that but what’s getting to me is, where upstairs meets downstairs in the wall there is pipes carrying the flow/return (Qualplex) and these have a tapping/ticking noise a lot of the time. I was wondering is this due to the boiler being oversized and when trvs close the pressure is too high. There’s no external ABV from what I can tell.

As a diagnostic measure I picked a larger radiator in the hallway 1600x500 and fully opened the trv and lockshield as a makeshift bypass but the issue stayed the same.

Has anyone an idea of what this could be?

Thanks all!

I’ve included a video of the sound within the wall below.

https://imgur.com/a/qXps9Nq

 

[Johntheo5]

Hi all,

I have an ideal logic Combi max2 30kwh that was installed in my hose prior to buying it.

It feeds 11 radiators in total, they are all type 22 and replaced at time of boiler I think.

1600x500 X 2
1800 x 500
1200x500 x3
1000x500
700x500
500x500 x3

There is one bypass road which is a 500x500 and the rest have TRVs

The issue I’m having is radiators upstairs close to the boiler all hiss, no matter what is done. It’s less so with fully open trv.

I can live with that but what’s getting to me is, where upstairs meets downstairs in the wall there is pipes carrying the flow/return (Qualplex) and these have a tapping/ticking noise a lot of the time. I was wondering is this due to the boiler being oversized and when trvs close the pressure is too high. There’s no external ABV from what I can tell.

As a diagnostic measure I picked a larger radiator in the hallway 1600x500 and fully opened the trv and lockshield as a makeshift bypass but the issue stayed the same.

Has anyone an idea of what this could be?

Thanks all!

I’ve included a video of the sound within the wall below.

https://imgur.com/a/qXps9Nq

Have you done the obvious and vented all the rads with boiler off?. there is also a automatic venting function, see below. I think the boiler has a 7M pump which is automatically controlled but you can set the minimum speed to 70% (it may have been set to 100%) which may help to reduce the hissing, see below.