DIY How To

How to assemble plastic pipe & fittings

DIY Projects - Plastic pipe

Plastic pipe is becoming increasingly more popular, it is lightweight and easy to join. It doesn't burst when frozen, it doesn't corrode and it can be used on both hot and cold water systems including central heating pipework.

There are all sorts of fittings for plastic pipe which should cover most situations, there are even adaptors to connect plastic pipe to copper pipe.

Cutting Plastic Pipe

It is crucial that the pipe is cut reasonably square to obtain a water type joint. If you have a lot of lengths to cut it is worth purchasing a pair of shears specially designed for cutting plastic pipe. If you are only cutting a few lengths a sharp craft knife can be used. Remove any burrs with a craft knife to prevent damage to the O-ring, when the pipe is pushed into the fitting.

Pipe shears

 


DIY Projects - Push fit collet fittings

Collet fittings are an easy assemble push fit, making them ideal for the diy market. Due to the speed and ease with which an installation can be completed most tradesmen also use push fit connectors. Collet type fittings have a ring of stainless teeth within the fitting which grip the pipe to hold it in place.

Safety AdviceDo not insert fingers into a fitting as the stainless steel teeth may cause injury. Make sure fittings are not left where children can pick them up and put their fingers in to them.

 

Push fit Collet type fittings are very easy to assemble, push the pipe into the fitting until it hits the internal stop, then pull on the pipe to make sure the connection is secure. Some manufacturers provide a marking system, by cutting the pipe on a mark, you know the pipe is fully inserted when the next mark along reaches the edge of the collet.
Pipe insert plastic Some collet type fittings recommend the use of a pipe insert to maintain the shape of the pipe and provide a more secure seal. Check manufacturers instructions.
Remove pipe To remove the pipe from a fitting, push the collet in to the edge of the fitting and withdraw the pipe.
Fit collet To provide greater security a collet clip can be fitted into the groove, this prevents the collet from being pushed in and releasing the pipe.

DIY Projects - Grab ring fittings

Grab ring fittings are an easy assemble push fit, making them ideal for the diy market. Due to the speed and ease with which an installation can be completed most tradesmen also use push fit connectors.

Metal insert Grab ring fittings must have a metal pipe insert fitted to the end of the pipe before the pipe is pushed into the fitting. This maintains the shape of the pipe allowing the grab ring to keep hold of the pipe. Push the pipe into the fitting 25mm (1") or use the marking system provided on the pipe. Check manufacturers instructions. Do not unscrew the retaining cap prior to fitting as this will not aid assembly.
Demount tool To remove the pipe from the fitting, unscrew the retaining cap and withdraw the pipe. Slide off the rubber O-ring, then remove the grab ring using a purpose made demounting tool. Never re-use a grab ring. To re-use the fitting, insert the O-ring and fit a new grab ring with the slots facing outwards, screw on the retaining cap hand tight, ready for the pipe to be inserted as above. Do not assemble like a compression joint.

DIY Projects - Repair push fit joints

Most leaks on push fit type fittings are due to either the pipe not being inserted fully, damage to the pipe or damage to the O-ring. Try pushing the pipe in further but if it still leaks, the pipe will need to be drained and the fitting removed.

Try to find the cause of the leak, check for damage to the pipe and cut back if necessary, if this makes the pipe too short a small section of new pipe will need to be fitted.

If the O-ring is damaged in a grab ring fitting, insert a new O-ring and grab ring then re-assemble the joint as above.

In the case of a collet type fitting, if the cause of the leak was damage to the pipe then re-use the fitting, if the cause of the leak is not obvious, use a new fitting.

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