Direct hot water cylinder.
The directly heated hot water cylinder is quite a simple system. Cold water is fed in at the bottom, where there is also use their small drain cock. The water is heated either by a dedicated boiler or by electric immersion heaters in the cylinder. Greenford Plumbers understand these systems. A connection at the bottom of the tank feeds the boiler, where the water is heated. The hot water is then returned to the hot water cylinder through a connection at the top of the cylinder. Supply of hot water for the taps exits at the top of the cylinder through a T joint, an expansion pipe also runs from the T joint to the cold water storage tank in the loft.

Indirect hot water cylinder.
The indirectly heated hot water cylinder has a heat exchanger (a coil) inside. Water heated by the boiler passes through the coil, and then transfers to the stored water in the cylinder. The water in the coil is part of a self-contained system and is never mixed with water in the cylinder that goes to the taps. A Greenford Plumber is well trained in both systems. This not only prevents limescale buildup in the boiler system, but it also extends the life of the system because it allows the use of anti-rusting additives in the boiler water. The Cold Water feed goes on the bottom of the cylinder, where there is usually a small drain cock. Supply of hot water for the taps exits at the top of the cylinder through a T joint, an expansion pipe also runs from the T joint to a feed and expansion tank in the loft.
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