Copper has become well established as a piping material suitable for all water supplies and in all circumstances. Making a sound water connection to a pipe is a relatively simple operation and, once you’ve mastered this skill, you will be able to undertake fairly substantial projects. There are three basic jointing methods used in the domestic environment:
C
C compression joints C
C soldered joints C
C push-fit joints.
COMPRESSION JOINTS
These are made using a fitting that clamps a compression ring on to the pipe and wedges it into the fitting at the same time (see Figure 6.2). To complete a sound joint, take the following steps:
1 Push the nut on to the pipe.
2 Push on the brass compression ring.
3 Insert the end of the pipe fully into the fitting, making sure that it reaches the stop.
4 Push the compression ring along the pipe to the mouth of the fitting.
5 Now wind the nut on to the thread of the fitting in a clockwise direction. This pulls the compression ring into the fitting. It is essential that the compression nut is not tightened too much as this will distort the compression ring inside, which may cause a leak. The joint should only be tightened sufficiently to hold the connection firm. When the
water is turned on, it can always be tightened a little more if necessary, but once tightened too much no further tightening will cure the leak.
Note that no jointing materials are necessary to make this connection: it is a dry jointing method. However, a trick sometimes used by plumbers, especially where the compression ring used is not new, is either to wrap a ring of PTFE tape over the compression ring or to apply a little jointing paste on to the ring to make up for any blemishes. This is not applied on to the threads of the fitting, as these are just used to pull the joint together and do not make the seal.
section through a compression coupling
pipe nut
compression ring
coupling elbow
e e t
Figure 6.2 Compression fittings
SOLDERED JOINTS
These are joints that have been made with the use of a blowlamp, although an electric soldering machine can also be used to supply sufficient heat to the joint without the need of a blowlamp.
There are two types of solder fitting: those that contain a ring of solder (referred to as solder ring fittings) and those that require the solder to be applied from a reel (referred to as end-feed fittings) (see Figure 6.3). When using the solder ring fittings, no additional solder needs to be applied to the joint.
Note that the solder used for hot and cold water supplies needs to be lead free in order to avoid contaminating the water.
However, where central heating pipework is being installed, it makes no difference what kind of solder you use. Both of these solders are readily available from plumbers’ merchants.
solder ring reducer
s (solder is added to joint)
end-feed reducing tee end-feed tap connector
Figure 6.3 Soldered joints
To make a soldered joint, take the following steps:
1 Adequately clean the mating surfaces of the pipe and inside the fitting. Do this with wire wool or a special nylon cleaning pad available from plumbers’ merchants.
2 Apply a suitable flux to the cleaned surfaces. This is a special paste, readily available from plumbers’ merchants, applied in order to keep the work area clean while soldering, thereby allowing the molten solder to stick to the copper and flow
easily. Note that solder will not adhere to dirty or oily surfaces. (There are self-cleansing fluxes that will clean the pipe and fitting as the heat is applied, but take care: they can be aggressive, and any residual flux needs to be fully flushed from both inside and outside the pipe.)
3 Ensure that there is absolutely no water in the pipe when soldering, otherwise it will not reach a high enough temperature – even the smallest drop of water will prevent the solder from melting.
4 Using a blowlamp or a soldering machine, apply heat to the assembled joint to melt the solder. Apply the solder as soon as it melts – do not simply hold the blowlamp there and burn away all the flux. If solder ring fittings have been used, the solder will be seen emerging at the mouth of the fitting. Then remove the heat source.
5 Take care not to set fire to any combustible materials in the vicinity.
6 Allow the joint to cool before moving it.
7 Finally, wipe off any residual flux – otherwise, it will make the pipe go green from the effect of corrosion on the pipe.
Should the joint leak when you test it, you will need to completely remove it and form a new joint, using a new fitting. The problem is most likely to have been a dirty joint.
Cleanliness and the application of a flux are essential in order to solder a joint successfully.
Remember this
The completion of a soldered joint is a relatively straightforward task if you follow the guidelines above. There must be no water in the pipe in order to solder successfully. The pipe must be clean and have a suitable flux applied. Any joint that fails will need to be completely removed.
PUSH-FIT JOINTS
There is a whole range of push-fit joints available. These joints are very effective and you should not worry that they will not
hold the water pressure – as long as you have assembled the joint correctly, inserting it fully into the fitting and ensuring that it is pushed all the way up to the internal stop. The joint is achieved by the use of an internal ‘O’ ring. When elbow or bend joints are used, they have the advantage that they can be swivelled around to any direction, even when water is in the pipe. Because of this freedom of movement, the pipework does need to be fully supported with pipe clips (see below).
Push-fit joints cannot readily be pulled from the pipe as there is an internal grab ring preventing withdrawal. However, they can be dismantled and reused. To remove the joint (see Figure 6.4), push the end collet tightly into the fitting and, while holding it close to the fitting, pull out the pipe. Different manufacturers use different methods to disassemble the joint, so you may need to obtain further advice from the manufacturer of a particular fitting.
Remember this
There is a simple way to ensure that a push-fit joint has been correctly and fully pushed into the fitting: put a pencil mark on the pipe at the distance from the end of the tube that would equal the depth that the pipe should enter the fitting.
section through a straight coupling elbow
push and hold collet in to
withdraw pipe ‘O’ ring
collet Figure 6.4 Push-fit joints
PIPE CLIPS
All pipework needs to be securely supported and held firmly by a pipe clip. These clips should be securely fixed to the wall or adjoining surface at a distance not exceeding the dimensions listed in Table 6.1 below.
Pipe size
Table 6.1 Maximum pipe support spacing, in metres