Vokera Compact SE - firing up but no heat no hot water

[simoh1]

When reset, goes to rapid (every 0.5 sec) green flashing LED, for which the manual says to "wait"(!). Either the boiler just stays fired up and nothing else happens - ie no heat - or after some time (around 30 mins) it goes to the solid red lock out, and on resetting goes through the same routine.
We've just bought the house and aren't living in it yet. Could this be anything to do with the freeze happening up here (Argyll in Scotland) just now?
Any other advice?

 

[glasgowgas]

check system is full and vented to 1.5 bar cold

check pump is free, and running

see FAQS at top of page for details on how to check pump

 

[simoh1]

Thanks for the response glasgowgas.
It got too cold to mess about and I got someone in. It was a thermistor
Cheers.