Unvented Cylinder

This type of vessel is normally constructed from copper with a foam insulating or a fibreglass material. On the top of the cylinder is a single piece of pipework that moves gently upwards and away from the unit. Finsbury Plumbers can service and repair this type of system. Now, the pipework divides into a tee, with one leg moving up and the other moving down. Follow the pipe moving up and you will arrive at a cold-water storage tank, and this pipe will finish its journey over the top of it. It is designed so that in the event of water filling the pipe it will just flow out through and into the storage tank. If you look and see this particular vent pipe then you have a standard ‘vented’ hot-water cylinder fitted. Should you not see this configuration, then it is odds on that you have an unvented cylinder installed.

An Unvented Cylinder has the features listed below:

1). The outer surface is made from a thin steel sheet, so you will not see any insulation material. A Finsbury Plumber can tell the difference.
2). The top of the cylinder is usually of a flat type or an expansion vessel might be very close by.
3). There is an arrangement of valves attached to the cylinder or to the expansion vessel.
4). A Tundish is fitted to the system. A Tundish is a hopper or funnel type of unit that will stop back flow and take overflowing water. You can observe the water in it. This is normally dry, however should any of the safety devices decide to operate, you will observe water dripping or pouring through it.

If this occurs there is a problem and you need to call a plumber with the relevant G3 qualifications to check the cylinder.”