Unvented cylinder

To identify the unvented cylinder system, you will need to note a few details such as:

Cylinders featured in these systems are normally constructed from copper and is covered in a fibreglass insulation material. This may be foam. A single pipe emerges from the top of the cylinder and then, turns at a more horizontal angle to the cylinder but really rising very gently.

N11 Plumbers can service and repair this system.

The pipework splits to form a tee, with one facing up and the other facing down. Following the pipe facing up you will eventually meet a cold-water storage vessel, and this vent pipe will finish over the top of it. It is such an arrangement that when water fills the pipe it will just return to the cold-water storage tank. If you found the vent pipe, then you have a standard ‘vented’ hot-water cylinder. If not, the odds are you will have an unvented cylinder, which has these general features:

1). You usually cant see the insulation, i.e. it has an outer skin that is usually made from thin steel. An N11 Plumber knows the differences.
2). The top is generally flat or an expansion tank is in close proximity.
3). There are a set of valves which are part of the cylinder structure or to the expansion vessel.
4). There is a tundish nearby, or a gap in the pipe so that you can see any water running through it. Normally you should not see water in this pipe, but if one of the safety devices has operated, you will see water either running or dripping through and should call a professional G3 plumber straight away as something’s gone wrong.

“