Log Burner Installation & Wetbacks

The circuit between the burner and the cylinder works by gravity: hot water rises out of the wetback to the cylinder, and cooler water returns to be reheated. That means the pipe runs need a continuous rise with no dips or high points to trap air, and the runs should be as short and direct as the layout allows.

Critically, nothing in that loop can be able to isolate it. A wetback that can't circulate while the fire is burning is a serious hazard, which is why this is work for a plumber rather than something to attempt as part of a general fit-out.

Wetbacks pair naturally with low-pressure, open-vented cylinders — the older style still found in plenty of Christchurch homes. That type of cylinder is vented to atmosphere, which is exactly what a wetback circuit needs.

Mains-pressure cylinders are a different proposition. They're sealed, so a wetback can't simply be plumbed in the same way and needs a specific arrangement to work safely. If you're on mains pressure, we'll talk you through what's involved and whether it stacks up.

If you already have a wetback-ready burner, or you're replacing a burner and keeping your cylinder, we can often connect the two — provided the cylinder is the right type and the pipe run can be made to work. We'll assess the cylinder, its location relative to the fire, and the route between them, then give you a straight answer. Sometimes the honest advice is that the cylinder needs replacing first, and we'll say so rather than plumbing something that won't perform.