Old Central Heating, boilers plumbing and drains systems in London, UK
The Water Supply to a property
There are two ways the water supply is feeding a house or a flat in London.
1. The direct system – where all cold water in the house comes from the main street water supply.The direct system means that water from any tap is fresh water and drinkable.
In old properties, the water supply pipe is made of lead, and it should be changed to plastic pipes, for health and practical reasons. The new pipe colour code for water pipes is blue and will deliver a larger amount of water supply at higher pressure. If there is a water meter in the street, the pipe length that runs from the water meter into the dwelling, is the property of the homeowner.
2. The tank system, where only the kitchen tap is fed from the mains and the rest of the taps and appliances are fed from a storage tank, usually located in the loft. The tank can be made of plastic or metal.
Because the water is stored into the tank, only the water from the kitchen tap is potable (Safe to drink; drinkable)
An advantage for the tank system, especially if there is a low water pressure supply, is that you can flush the toilet, etc and have a constant water pressure supply.
StopCocks, Taps, Drain Cock and Valves
There should be two main water supply stop valves – or stopcocks in every property. One is located outside, in the street – front of the property and located in the pavement, with a metal or plastic cover. The second one is located inside the property, most of the time can be found in the kitchen, under the sink or under the staircase. These stopcocks are installed to allow a plumber or homeowner to turn off the water supply, when there is water leak or maintenance to be done to the plumbing system.
The cold water tank in the loft also has two valves. One valve for the cold water supply to the bathroom taps, garden taps, etc, except the kitchen sink and one valve for the hot water tank supply water pipe.
Drain cocks or Drain Valves, can be found at the bottom of the hot water tank. To empty a hot water tank you need a hosepipe, attached to the drain valve. To empty the Central Heating plumbing pipes and radiators, again,a hosepipe, attached to the drain valve which should be located at the lowest point in the plumbing system. To empty the cold water tank, turn off the mains and just open the cold water tap in the bathroom or garden tap.
To turn the water supply off for a kitchen sink, bathtub or bathroom basin, there should be two valves fitted on the supply pipes, one for the cold water and the other one for the hot water, located under the bathtub taps, basin,or sink.
Boilers and Central Heating System
PUMPED SYSTEM – The water is circulated by a pump, through the Central Heating system. From the boiler to the radiators and back. The same water is reheated by the boiler, pushed by the pump through the Central Heating pipes to the radiators and back to the boiler to be reheated. There is a pipe for safety reasons, called Open Safety Vent Pipe to let built up steam and pressure escape if the boiler overheats itself. Motorised valves and thermostats are are used to control the heat. In the loft, there is small Feed and Expansion cistern.
GRAVITY CIRCULATION SYSTEM – The grandmother of Central Heating, a very simple system than only very experienced and very Qualified plumbers should attempt to tackle. It works on the principle of physics, hot water is lighter and expanding than cold water when is heated by the boiler, thous it goes up the pipe work. Less mechanical parts than can break down, but larger pipes are needed instead of the 22mm and 15mm diameter pipes used as standard in Central Heating. There is also a saying among the plumbers : These types of boiler don’t like to be moved because the gravity system works better when the hot water tank ( cylinder ) is right on top of the boiler to work at its best.
SEALED SYSTEM CENTRAL HEATING AND UNVENTED SYSTEMS
This types of Central Heating is more modern, very unlikely to find them in older properties. Megaflo system is a very popular choice when a large amount of hot water is needed, dwellings with more than one bathroom, underfloor heating, etc.
Drains pipes, waste systems
There are two systems of drainage that you need to think about: ’foul‘ and ‘surface water’. In general, these two systems should be kept separate.
Each of these has above-ground and underground elements.
Foul drainage carries the used water from toilets, sinks, basins, baths, showers, bidets, dishwashers and washing machines. The above-ground pipework is referred to as sanitary pipework; the underground pipework is referred to as foul drains and foul sewers.
Surface water drainage carries rainwater (and melted snow and ice) from hard surfaces. The above-ground system of gutters and rainwater pipes is referred to as roof drainage; the underground pipework is referred to as surface water drains and surface water sewers.