105e instant flue/fan fault

[mrtroper]

got this 105e that flashes flue/fan fault but the boiler still modulates, ch is fine, dhw is not up to temp, done all the fan/flue checks as the boiler still modulates it cant be a problem that cuts out mudulation.
From start fires reaches to 50 then flashes carrys on mudulatiing,then all temp leds up to 50 still keeps on working then will show the true temp by leds then back to 50 led flash, can go like that all day, ch is fine getting hotter.
i know if the dhw is not reaching temp what to do, but with the fan/flue fault re-curring but with mudulating still working is puzziling

 

[baxpoti]

Presuming you have a standard 1m horizontal flue installed correcttly.

Intermittent problems on this boiler with this fault usually come down to the APS or PCB. It would also be prudent to check the venturi is not blocked or damaged.

The services of a competent RGI are recommended.

 

[mrtroper]

hi, i am rgi but done the checks but if i was,nt for fan/flue lled flashing,you would not think there was a problem,