Changed Rad no heating or hot water ?

[Baldielocks]

Hi folks, just changed a single rad for a double in the kitchen. Switched boiler off ( gravity fed) drained water from system. Took the old rad off and fitted the new one. Refilled the system bled downstairs rads first the the up stairs ones. Switched on the boiler, then the heating and it fires up (the green light comes on) there is a glugging noise in the boiler and it switches off, ( ie green light goes off) does the same when I put the hot water on. Any ideas ?
Cheers.

 

[CBW]

Probably air locked. Are you certain it’s gravity system?

 

[Agile]

Did you bleed the plump of air?

Many older ones have a silver screw in the middle and you need to loosen it a few turns until water comes out with air.

Do it with system off first and then with pump on.

Did you turn pump isolation valves off and forget to open them afterwards?

 

[ianmcd]

Do you actually have a gravity system ? Gravity means gravity Hot water, you probably have an open vented system,if when working normally you can get CH without the HW being on , then you dont have a gravity sytem, if you have any motorised valves you need to set them to MAN before filling