Gravity circuit on a unvented hot tank

hydrus21

Looking for advice on this please.

Has anyone managed to get a gravity circuit work between a multi fuel burner and a corrugated primary coil?

Pumping it is OK as long as there is no power cut which is my main concern.

John.G

From what Ive read on other sites theres not a hope of getting any gravity circulation with a corrugated primary coil.

10-10-20

What now is this purported magic of a "corrugated primary coil"? I googled it and it's not showing up. Is that a common feature on modern cylinders?

Wearb

https://www.boards.ie/discussion/comment/121779368#Comment_121779368

Because it creates a much greater surface area, it greatly improves heat transfer.

10-10-20

https://www.boards.ie/discussion/comment/121779522#Comment_121779522

🤣 Thanks! That's what triggered my interest. It also means that the water-flow is more turbulent/less laminar and the heat dissipation should be better again. That's why I was wondering how common they are.