S7 Error - Vaillant Ecotec plus 831

[Jackt25]

Hi

I have a Vaillant Ecotec plus 831 connected to a Myson thermostat but am currently expericneing an S7 error code, after a minute or so this changes to S8.

S.7	Heating mode – pump overrun error
S.8	Heating remaining cut off for XX amount of time

- Hot water is unaffected
- The pressure on the boiler reads as 1.1
- I have previosuly tried to repressurise the boiler
- The boiler is located in a 2 bedroom flat
- Prior to the fault codes appearing some of the radiators were only heating up at the bottom. I have not bled the radiators.

Please could someone advise on hte liekly cause and any steps needed to fix. Happy to post photos or provide extra info as needed.

Thanks
Jack

 

[Mike13]

s07 is when the return water is too warm and the boiler cannot modulate low enough to maintain the dialed in radiator temperature. a total pain to fix if it happens. sometimes increasing the water temp will help, but efficiency goes down.