Vaillant ecoTEC plus 418 VU GB 186/2 OH - Error codes F62 and F22

[silverfox2019]

Every couple of weeks, my Vaillant (system) boiler fails to ignite and the error code F62 is displayed. I then press the reset button and the boiler ignites with the main burner working for maybe 30 seconds. The boiler then shuts down and displays error code F22. I then press the reset button again and the main burner ignites and the boiler works fine for several days.

The user manual states these codes mean the following:

• F62 = Gas Valve shut off delay – gas valve leaking, electronics defective.​
• F22 = Dry fire – Too little water in the appliance, water pressure sensor defective, cable to pump or water sensor defective, pump blocked or defective, pump output too low.​

Does the combination of error codes F62 then F22 narrow down the fault – or maybe they suggest what items I should start checking first to check the most likely cause(s)? Any tips would be appreciated.

 

[CountryFan]

F62 and F22 are not related, unless you start to get other spurious faults along with them. F62 isn’t a DIY fix and wouldn’t be wide for me to say what it is on an open forum. Is the heating circuit pressurised/sealed?

 

[silverfox2019]

Thank you. My 16 year old System boiler isn't sealed (pressurised). It's not a combi. It's a traditional old school system with a hot water tank.

If it's a complex fix and needs a new £300 gas valve plus labour, I'll probably get a new boiler installed.

 

[DP]

It's not a combi

. If a heating engineer like Countryfan missed number 418 is not an heat only boiler ( ie not a combi- which would start with figure8) then he must be having a very bad day.

Also, a system boiler would start with digit 6 and would be sealed

BTW. Countryfan works with these boilers almost every day