Bad Crackling in some radiators

[Tigermad]

Plumber fitted an auto bypass a few weeks ago and put some more inhibitor in after I asked him to. Since then the radiators have started crackling really badly when heating up. I have tried bleeding them and it seems to be coming from the side of the radiator without the trv and the valve there and radiator itself. Any ideas? I have an evohome system and unvented system.

 

[townfanjon]

Are they new rads ?

 

[Tigermad]

Are they new rads ?

Yes. The unvented system was fitted a year ago. Kept the three or 4 existing rads and changed 3 or 4.

 

[townfanjon]

Just the new rads that’s noisy or all of them

 

[Tigermad]

Just the new rads that’s noisy or all of them

Hi. Just seems to be downstairs mainly. 2 new rads and one old. The nearest to the boiler is the noisiest

 

[townfanjon]

Where did the rads come from ?
Your unvented system is only hot water , will make no difference to rads

 

[Tigermad]

Where did the rads come from ?
Your unvented system is only hot water , will make no difference to rads

I’ve had the new rads in for over a year. They have only started to crackle since the bypass was fitted a few weeks ago.

 

[townfanjon]

Can you put a pic of the bypass, valves and pump.