Cycling issues

[Bradshell]

Turbomax 824 has started cycling on the central heating after i refitted a rad after decorating. Bled the system etc and all was fine but now when the heating is on it gets to about 82 and then cuts off. Drops to about 60 then kicks in again.
This may seem what its designed to do but it wasnt doing it before. It has just a timerclock fitted and the manual switch to turn the heating on.
All bar a few rads have trvs on them. All trvs and locksheilds are open now.

Really at a loss now. Changed the pump and used x800 as i thought it may be a blockage. Used a thermal camera and all the rads warm up perfect with no cold spots. Any help is masively appreciated.

 

[MeldrewsMate]

If all your rads are getting hot then there is no problem with the water circulation.

What time elapses between the 82 cut-off and the 60 kick-in?

Did you make any changes to the boiler settings? Could you have put it into max power mode? I mention this not because I have any specialist knowledge of these foreign made boilers, but because the symptoms you describe are those of a boiler test mode, i.e 'run at full power until the high temperature thermostat operates. Wait for the high temp stat to reset, then repeat.'

 

[Bradshell]

I didnt make any changes to any settings. Just turned it off. Drained and then bled the radiator. Fired up and now i have this issue. A friend who is a plumber has said it is almost definately got a blocked or sludge somewhere restricting the return flow and causing the boiler to get too hot.
It does work as you have described. Boiler test modes exist on vaillant boilers?