Slide the compression fitting olive (brass ring) over the first length of pipe, and then lay the nut over that

Plastic pipe can be joined with compression fittings, however it is important to use the correct brand of pipe insert to support the end of the pipe, or else the joint may start to leak over time. We are currently using Royal Mail Parcelforce and DPD as our delivery providers, all small items will be delivered by Royal Mail, these can take up to three working days to reach you. Once the nuts are done up hand tight on the joint, an additional half to three quarter turn with a pair of spanners (one on the body of the fitting to hold it still, the other on the nut) is usually adequate to make a seal. If the joint leaks, an additional tightening tweak will normally fix it. Note that over-tightening a joint may actually make it leak.

One of the difficulties with compression fittings is that while the nuts are usually a nominal size, there is not agreed standard tolerance between manufacturers. This can make selecting a single universal spanner difficult. Also not all spanner types can be used in all situations. Hence most plumbing kits will have a number of spanners, including at least one adjustable one. Available in three sizes, 16mm – 40mm, 40mm – 75mm and 63mm – 125mm. This compact tool is a necessity for all your compression installations and repairs. Using a spanner, tighten the nut over the threaded head of the fitting, while holding the fitting with a pair of plumber’s grips. This pressure created by the tightening motion will press down on the olive, causing it to grip the pipe tightly. However, be careful not to exert too much pressure as this could damage the fitting or thread, making the device harder to remove or reposition On the downside, the extra leverage can make it too easy for a untrained gorilla to overdo it! Sometimes the length can also be a problem in confined spaces. Copper and brass olives both work fine. Olives can't be removed from a pipe and reused. Even hand tightening a fitting with an olive inside before the pipe is inserted, is enough to make the olive unusable.

The other way is to use a few turns of PTFE tape to the threads. Note that used this way the PTFE will not aid the sealing of the joint, but it will make the nuts easier to torque up. PTFE tape can also be used as a sealant - a few turns need to be wound over the olive such that they will end up sat between the mating surface between the olive and the fitting: Non setting lubricants and jointing compounds like that shown above can also be applied under and over the olive. This can be more effective for fixing leaks due to pipe scratches. Copper pipe works well with compression fittings. Chrome plated copper pipe also works well. Some advocate stripping the chrome from the area of the pipe in the fitting as this allows the olive to get a better grip on the pipe. There is no actual need to do this, but if not doing so, it is advisable to torque the nuts a little higher than with normal copper pipe since its harder for the olive to "bite" the chromed pipe.Compression joints are designed to be used without any sealant. The nut compresses the olive driving it into the cone shaped profile at the end of the fitting body, causing deformation of both the metal surfaces of the olive and the pipe, zeroing the gap and creating a watertight seal. Again, a clean square cut is important, and any burrs removed. Take great care to protect pipe ends when pulling them under floors etc, since its very easy to scratch plastic pipe and this makes it hard to get a good compression (or pushfit for that matter) seal. Use of PTFE tape on both olive and threads can be of course be combined to both lubricate and seal.

Compression fittings should be tight enough to create a watertight seal but not so tight that the pipe warps or the thread is damaged as this could encourage leaks and make the fittings much harder to remove later. Proceed with caution. What Should I Do if I Find a Compression Fitting Leaking? The pipe needs to be cut square and cleanly, with any burrs removed. Pipes cut with a pipe cutter are much easier to use than those cut with a saw. The pipe needs to be clean and free from contaminants like paint or plaster etc. It does not need to be quite as clean and shiny as required for soldered connections. An olive splitter takes a different approach by tighenting a sharp edge onto the side of the olive while supporting the pipe from the inside. They cut through one side of the olive without damaging the pipe, allowing it to expand a bit in diameter and slide off the pipe.

They are very skinny which makes them uncomfortable to use as well, but sometimes this slimness is an advantage where there is not much space. Note that any sealants used on drinking water must have WRAS (Water Regulations Advisory Scheme) approval for this use. The most effective "cure all" sealants are the silicone based "setting" sealants like Fernox LS-X. These will usually seal most problem joints so long as the olive is actually meeting the fitting body when the nut is tightened. The vice grip spanner is a combination of an adjustable spanner and a set of vice grip pliers (aka "mole grips"). Very handy for working at arms length in awkward spaces, and also for not marking polished chrome fittings like nuts on taps or service valves. Also means that you have twice the number of positions that the spanner can engage with the nut. This is very handy when there is very limited turning space for the spanner.