bathroom radiator

[forest]

hi
i had my down stairs bathroom ratiator redirected onto the hot water system (tribune11) so when my hot water came on
summer and winter ihad a heated radiater
after a good 10 years it has failed i have drained the rad checked the valves but still no through flow
i would appreciate any help
forest

 

[erj]

are you getting hot water

 

[Drip Doctor]

Possible airlock if it's a gravity system?