ok ive checked the pump, defo working, mesured the temp coming out of the boiler, gets to about 75c on low then cuts off.
I think the kettling is down to air that wont come up to a bleed point.
New problem thermo couple has gone as pilot is cutting out. once i get that sorted i will try again...
So today i replaced the leaking valve next to the pump and did the other one too as it was off, replaced a rad valve, checked the 3 way valve, aok.
The pump works great. dam pilot wont start now, the spark is week so got to replace the piezo device.
I thought it would be best to show you a lil video of the problem.
Its just super noisy! Ive been told its kettling but not sure on what that is or what needs to be done to fix it?
http://youtu.be/tbDaE0wTHT4