Ariston Genus One System flame lifts 5P3, 501, 504, 309, 303 error code. To fix it read description

Some tips to fix this errors collected from my and other users experience :
- clean ionizating electrode (more often when boiler is in laundry room)
- clean condensate drain
- check grounding and power supply (grounding resistance up to 13ohm is ok)
- check gas valve selenoid resistance ( Type SGV100: pin 1-3 : 25ohm, pin 2-4: 67ohm)
!!!! UPDATE: my gas valve was getting stuck, not opening fully!!!! get proper test of gas valve, see my video how to test gas valve
If after cleaning and checking still have errors, probably your main PCB is faulty!
Fixing 309(gas relay check failure) and 303 error code for PCB (part nr. 65116545-04):
- check connection from main board to gas valve ( 4-pole white connector)
- check or just replace smd capacitor placed between white 4-pole connector and omron relay,
replace with 1nF capacitor.
here is PCB fix - error code 309, 303:    • Ariston Genus One System 309, 303(als...  
- may help also to resolder/reflow microchips, check under microscope. There could be a cold joints.
Let me know in comment if you manage to fix some errors and LIKE my vid.
This boiler is a mess... do not buy !!!