got woke up this morning by wife saying no heating and found my worcester bosch greenstar 18 with a flashing light on the front. I reset the fault but as the boiler starts back up again you can hear lots of water gurgling sound from inside the boiler that never heard before.
checks ive done so far
There is water in system and header tank
Removed pump and it seems ok, connected up externally and it spins when powered up.
Bled air from inside boiler and all rads.
My only guess is the pump even though its spinning as the system just sounds like the water flowing inside the boiler is inconsistant ,
any tips greatly appreciated as its cold here .
im on a traditional Y plan system , non presurised system.

now sorted , it was the condensate pipe leading outside had frozen solid, bloody weather .

On Jan 9, 9:40*am, dbroms wrote:
got woke up this morning by wife saying no heating and found my
worcester bosch greenstar 18 with a flashing light on the front. I
reset the fault but as the boiler starts back up again you can hear
lots of water gurgling sound from inside the boiler that never heard
before.

Your condensate drain pipe is blocked (frozen). The gurgling is a
result of the condensate having backed up inside the burner.

Go outside and pour hot water on any section of the condensate pipe
that could be holding water - horizontal bits or indeed any uphill
sections which some installers seem to think is acceptable to include!

With the pipe defrosted, reset the boiler - its syphon should empty
allowing the boiler to operate again.

Mathew