I don’t disagree, there are rumours suggesting that the reason British Gas started doing it in the 00’s was simply because it was cheaper, as they used less copper pipe!! :)
Correct, that’s what I was thinking, thanks to your help!
I assume I could also use the designs in figure 4 of the guide… and just cap off the cold feed inlet. I just picked figure 5 because it already had the cold feed capped off.
We are getting a bit off track here. But I can assure you my system is perfectly normal!
The reason it’s somewhat rare is because it’s only suitable with boilers that have overheat protection built in (like the Suprima).
There are multiple threads on this very website about it. Usually from...
This is my current aerjec. The pipe you see leading out the top of it is the combined feed and vent. This is the pipe that goes into the bottom of the F&E tank.
There is no other vent pipe or indeed any pipe that goes into the loft, except the cold main, to refill the tank.
The cold feed will be the vent pipe! Combined feed and vent.
If it makes it easier to understand… my F&E tank doesn’t have a vent pipe over the top of it. There’s nothing there.
It simply vents through the 22mm feed pipe. More info here...
It’s 22mm throughout but does manifold off into microbore. All the rads are microbore. The heating is pumped with an F&E tank.
Thanks to John, I am fairly confident that the aerjec is the cause of the problem. It’s definitely piped incorrectly for a combined feed and vent. The boiler flow is...
Thanks for all your help!
I think the confusion is, this combined feed and vent is a concept British Gas started doing about 20 years ago. It’s created by having a 22mm pipe from the bottom of the F&E tank, allowing for the same pipe to feed the system and also vent any air out.
It has its...
Do you mean from the F&E tank? It’s a combined feed and vent so there isn’t one. The vent is also the feed.
The only other cold feed is on the domestic side.