Ideal Logic Heat 15 Fault - F2/F3 + Noise - Help

[alpaxj]

Hi all,
I have a strange issue with my Boiler. Its got the F2/F3 fault which according to research could be an issue with the fan/flue or something related to Flame/gas.
The pressure is ok sitting above 1 bar. I have an IDEAL Logic Heat 15 which heats up the Water Cylinder upstairs. The cyclinder feeds two-zones.

I have had a British Gas (home care cover) engineer come round and take a look and they replaced a PCB but the problem still hasnt been fixed. They looked pretty stumped to be fair and couldnt really work out the issue.

Symptoms:
1) if the boiler runs for around an hour and stops, the fault F2/F3 appears and at the same time a noise can be heard every 10-30 seconds like its trying to start up.
2) Sometimes its the F3 fault code, other times its the F2 code.
3) Restarting or turning off/on the boiler sometimes fixes it for a period of time only to return later.

Ive attached a video of the issue.

Any one come across a similar issue and what the noise is?
Might have to take the thing apart completely to find the fault, or spend $$$ getting a new one :/

Thanks for your advice and support in advance.

[Someone-Else]

If they have not fixed it, annoying that it is, call them out again as "same problem as before"
They will not like it if you "Tell them what you think the cause is"

[aeromech3]

Agree with S-E call them, you pay for that service.
Not a heating engineer, but simply check the condensate drain is clear?
As the PCB has been replaced and you hear a noise in the boiler, I would be suspicious about the fan seizing up.
Your zone valves are they working smoothly.

[gas4you]

I would be looking at the fan.

If its running for an hour or so first it could be the bearings seizing when getting hot.