wallstar combi

[tell123]

hi i have a wallstar oil combi boiler and it has started to lockout on regular basis i.e. every time i want use it any help would be good it also seems to have alot of air build up in the line is this normal ? i do bleed it every time it locks out but this has not made a differance it still locks out ,it is doing it about 6 times a day but when i reset it seems to be fine for a while ,it has done it b4 but for the last 3/4 weeks its been fine but now the problem is back and is worse than ever.
any help or ideas for what could be wrong would be would be gratefully appriciated .

 

[Burnerman]

Is your oil tank above or below boiler level?
John

 

[tell123]

i suppose you would class it as below but it hasn't been a problem untill recently

 

[Tibbot]

Check any combined isolator/filter valves at the tank. Any trapped gunge could have iced up in freezing weather. Check any filter near appliance as well.

 

[tell123]

thanks will try that did not think to look there .
i did however have to reset it b4 i went to work tonight and as far as i know it has not gone off again as i would have had a call from the mrs,.
any other ideas i could try