Master Basic Plumbing And Central Heating

A quick guide to plumbing and heating jobs, including basic emergency repairs

Roy Treloar

• Publisher: Teach Yourself
• Year: 2010
• Print ISBN: 9781473611627
• eBook ISBN: 9781444129090
• Topic: Technik & Maschinenbau
• Subtopic: Technische & produzierende Gewerbe

This guide to the basics of plumbing and central heating is designed for complete amateurs, and written by one of the most experienced plumbing tutors in the country.Whether you are attempting projects such as installing a new bathroom or plumbing in a new dishwasher, or just need to understand enough to do essential repairs and fixes, this is the book for you. It includes step-by-step guides to sorting out the most common plumbing problems, and comprehensive coverage of the key tasks, all based on a straightforward introduction to the layout of your house and water system. In addition, it has plenty of illustrations, a full glossary, a whole chapter on how and who to call for help, a guide to the necessary toolkit and a list of the top ten plumbing emergencies.

1

The plumbing in your home

In this chapter you will learn:

• how the water supply arrives in your home

• about the different types of water supply

• about cold water storage

• about WC systems

• how water leaves the property.

This chapter looks at the plumbing systems in your home, from the point where water is fed into the house and passes through the pipework, to the point where the used and unwanted water leaves the house via the drains.

Incoming cold water supply

The water pipe feeding into your home comes from a supply pipe in the road, at a point just outside your property. There is usually a water authority valve at this point, and it is here that your responsibility for the water and pipework begins. The pipe travels below ground at a minimum depth of 750 mm to ensure that it is protected from damage and that the water will not freeze if the temperature drops below freezing point (0°C). The pipe then passes into a pipe duct through the foundations and ground floor into your home, terminating with a stopcock (tap). See Figure 1.1.

In newer buildings a water meter will be incorporated within this supply pipe. This may be contained within a chamber outside, keeping the meter below ground level, or within the building itself, thereby allowing easier access for reading and maintenance. There may also be a stopcock situated under the ground at the boundary to your property, in addition to the one inside.

The pipe in the road from which this drinking water supply is taken is usually referred to as the ‘mains’.

THE WATER SUPPLY PIPE

For the past 30 years or so, plastic (polyethylene) has been used for the cold water pipe feeding your home. Today it is typically blue and the standard diameter is 25 mm (equivalent to a copper pipe of 22 mm diameter) and it is adequate to supply several outlets at once. In the past, however, smaller-sized pipes were used, including:

• 20 mm plastic pipe – either black or blue (equivalent to 15 mm copper pipe size)

• 15 mm copper pipe

• ½ inch galvanized mild steel pipe

• ½ inch lead pipe.

These older pipes are regarded as too small for a modern house because of the extra appliances used (washing machine, showers, etc.) and extra toilets. The size can restrict the flow of water and cause a loss of water flow at some outlets if several appliances are opened at the same time. Unfortunately, there is not a lot you can do with your existing supply pipe if it’s too small, other than replacing it with a new pipe.

SUPPLY STOPCOCK (STOPTAP)

It is very important that you know the location of this valve; after all, it supplies the water to the building, and turning it off will stop the flow of water. This is essential in a situation where water is leaking from pipework. Typical locations for the stopcock inside the building are:

• under the kitchen sink

• in a downstairs toilet

• under the stairs, in a cupboard

• in the garage

• in the basement

• under a wooden floorboard, just inside the front door.

Figure 1.1 The cold water supply into a home

There may be an additional stopcock outside the building. Don’t turn off this valve until you fully understand the consequences of doing so (see Chapter 2).

Ideally, once the internal stopcock has been found, you should tie a label to the operating handle, so that anyone needing to find it in the future will know that this is the main water inlet to the building (see Figure 1.2).

Figure 1.2 Supply stopcock with drain-off valve

Remember this

In an emergency, turning off the incoming cold water supply stopcock will eventually stop the water flowing from any water pipe, wherever it is. This includes the pipework for the hot and cold water and the central heating.

Cold supply inside the dwelling

Once you have identified the incoming supply, look for a small outlet valve, known as a drain-off cock, just after the stopcock or incorporated within its design. This may be missing in older buildings or in poorly installed systems. The drain-off cock allows the cold water supply mains pipework to be drained, for example for maintenance work or if you’re going away for a long time in winter. There is provision for a hose connection, but generally, when the supply has been shut off, much of the water can be drained out via the kitchen sink, so that only that remaining in the pipe needs to be drained.

From the stopcock the pipe will run to the kitchen sink and other outlets. The route will depend on the system design, which will be one of the following:

• direct cold water supply

• indirect cold water supply

• modified cold water supply.

The pipework usually runs beneath floors or through pipe ducts, for example alongside the vertical soil or drainage stack (the drainpipe taking waste water from the building) as it passes up through the building. It may also be encased within the plaster wall. In all cases the actual pipe route is not a major concern, provided that it is protected from unforeseen damage and frost.

DIRECT COLD WATER SUPPLY

If you have this system, all your cold water outlet points are fed directly from the mains supply. These include all appliances such as the sink, bath, basin and WC, plus any other outlets to washing machines, dishwashers, or outside taps used for watering the garden (see Figure 1.3). The cold supply may also feed a hot water system such as an unvented domestic hot water supply or combination boiler (see Chapter 2).

Figure 1.3 A direct cold water supply system

Key idea

In the ‘direct system’ of cold water supply, all the cold taps are supplied with water that has been supplied directly from the local authority water supply mains pipe and therefore can be regarded as very safe to drink.

INDIRECT COLD WATER SUPPLY

In this system the only appliance fed directly from the mains supply is the kitchen sink, plus a water softener if one is incorporated within the property. Instead of feeding directly to the other appliances, the supply feeds a water storage cistern, usually found within the roof space (loft). All other outlet points in the building are then fed from this storage cistern (Figure 1.4).

MODIFIED COLD WATER SUPPLY

This type of system is a combination of both the direct and indirect supply systems. In other words, there may be several outlets from the mains supply and several fed via a storage cistern.

Prior to the 1980s most systems were of the indirect design. These were intended to maintain a flow of water under the worst possible conditions, for example when the supply was cut off for some reason – such as the water authority doing essential repairs or in areas where there was an excessive drop in water pressure at peak times. The local water authority may also have imposed a specific requirement that the supply had t...

Table of contents

• Cover 
• Title
• Contents 
• Meet the author
• Introduction
• 1 The plumbing in your home
• 2 Hot water in your home
• 3 Domestic central heating
• 4 Emergencies and contingency work 1
• 5 Emergencies and contingency work 2
• 6 Plumbing processes
• 7 Ancillary works and maintenance
• 8 Undertaking small plumbing projects
• Appendix 1: Legislation
• Appendix 2: Glossary
• Appendix 3: Taking it further
• Copyright