F25 Boiler Fault BG 330+

[Teknet]

Hi all…

I am randomly getting the above fault code come up on the boiler. Generally I have seen it come up a couple of times randomly when I’ve got up in the morning and the house is cold, so basically the boiler has tripped in the middle of the night. I have googled it and understand it’s when the flow temp increases rapidly within a few seconds…

A couple of things to add. I have got the TADO TRV’s installed in the house so that basically the downstairs rads are off during the night and vice versa during the day. Initially I was 2 TADO TRV’s short downstairs but I have now got the additional 2 I needed. The first time the boiler tripped was in the middle of the night right after I had installed the extra 2 downstairs. It was then fine for a few nights before it did it again so I’m a bit stuck as to what’s causing this. Any help would be much appreciated, thanks

 

[cross thread]

Have you any pass fitted ,could be lack of minimum flow

 

[Stuckinarut]

The manual suggests air or pump failure, so could be the pump on its way out. What you also have is a circuit that's off, maybe try decreasing the flow temperature at the boiler?

 

[Teknet]

Hi my Grundfos pump seems fine and regarding air I have bled all my rads properly. I would say though that one or two of my rads do keep getting a bit of air in them and I’m not sure why? I did have the heating system powerflushed a couple of months back so it’s been running nice and smoothly. I don’t have any leaks in the system so again not sure why the same rads get a bit of air in them

 

[Teknet]

Have you any pass fitted ,could be lack of minimum flow

Not sure what you mean by this? Also just to note this has not been happening every day just a few times spaced apart so it’s not like it keeps happening every single night when the rads come on - also I’ve not encountered this during the day at all

 

[cross thread]

Should of said By-pass

 

[Stuckinarut]

Hi my Grundfos pump seems fine

Just because it seems fine, doesn't mean it is

and regarding air I have bled all my rads properly. I would say though that one or two of my rads do keep getting a bit of air in them and I’m not sure why

Could be a hydrogen buildup