In terms of plumbing, PEX (polyethylene encapsulated into a crosslinked matrix) is a relatively new material being used in both new and old buildings. Building codes now mandate its use for both new and old constructions. With PEX, you are dealing with a flexible tubular plumbing system that you can connect either through a compression fitting, a metal insert, or another mechanical method without glue or heat. CPVC is a type of hard plastic pipe that is composed of jointed joints that are glued together in order to form a pipe.
The two plastic types CPVC and PVC have several applications that they can be used for. There aren’t many applications in which CPVC and PVC are used together, which is why they aren’t commonly found together. By chlorinating the CPVC in an additional step, it is able to withstand the extreme heat levels much better than normal PVC. It is known that at temperatures of 140F, PVC begins to deteriorate, but CPVC is able to maintain its strength at 200F, making it the perfect material for water supply lines. Since PVC drain lines are normally used because they are less expensive and do not rust, it is the most commonly used material. Would it be possible to glue PVC to CPVC if that were necessary?
It is important to note that CPVC, which cannot be bonded, is the most commonly used (and cheapest) material in the manufacture of Pex. The compression fittings that are available for cpvc can not be used in the home, or at least not any that can be used. There will be an adapter needed for each type of pipe to connect to a pipe thread. In order to connect the PEX adaptor and the CPVC adaptor, the PEX adaptor will need to be crimped or whatever brand of PEX is used.
Explaining CPVC and PEX
Chlorinated Polyvinyl Chloride – CPVC
As the name suggests, chlorinated polyvinyl chloride (CPVC) is a thermoplastic material that is adaptable, durable, and strong, and is commonly used to supply hot and cold potable water to residential buildings. Because it’s made of polyvinyl chloride, CPVC can withstand higher temperatures than PVC and defend itself against the damaging effects of highly chlorinated water.
To destroy pathogenic bacteria before the water reaches your home, public water companies disinfect the water using chlorine. Depending on where you live and the season, you may notice a slight difference in the level of disinfection in your water system. PVC has the advantage of being less corrosion resistant than CPVC.
Cross-linked polyethylene – PEX
PEX pipes are flexible and durable because they have been made from medium- or high-density polyethylene. The PEX piping systems used in the distribution of hot and cold water in Europe as well as for hydronic radiant heating systems have been around for decades.
PEX pipe first made its appearance in the United States in the early 2000s. PEX flexible piping was the most frequently used flexible piping material for plumbing and radiant heat applications in the 1980s. Because it can easily be snaked through the walls, PEX tubing is one of the most common alternatives used in remodels because it can easily be inserted through the walls. PEX tubing can be used for water distribution pipes and it is compatible with all major plumbing codes, which makes it a great choice for your house. Learn more about what happens after PEX tubing has been manufactured.
PEX and CPVC Compatibility
A specialized tool is used to seal PEX tubing to fittings in most PEX plumbing installations. Another type of connection is made with a compression ring and screw. CPVC pipes are connected to CPVC pipe fittings using solvent-based glue. Heating the PEX tubing will cause the connection to soften, causing it to lose its stability.
PEX, a flexible plastic that cannot be crimped into position or spread out to cooperate with CPVC fittings, cannot be crimped into position or spread out to cooperate with a compression ring and nut.
Alternatively, push fittings can be used with both PEX and CPVC pipes. Fittings that use an internal gasket to keep pipes in place are similar to quick-release fittings found on water or air hoses since they use an O-ring to keep them in place. In simple terms, all you have to do is push one side of the PEX tubing into the fitting and the other side of the CPVC tube into the fitting and voilà, you have achieved a connection without glue or any special tools needed for either CPVC or PEX systems.
Are PEX and CPVC the same size?
As a side note, PVC and CPVC pipe are generally identical, apart from their respective material compositions. CPVC fittings have fittings that mimic copper in appearance. The pipe is inserted into the fittings. Despite the use of “full flow” expansion fittings, PEX pipes have a reduction in diameter at each fitting.
PEX plumbing is bad, so why is that?
The failures of PEX plumbing, having been around for a longer time, are well known and well documented. Pipes and fittings are the major cause of PEX failure. The pipes fail when chlorine-containing water comes into contact with them.
How to Join PEX and CPVC
The use of push fittings is increasing as plumbing becomes more widespread. These fittings are available in regular home improvement stores now from several manufacturers. Despite the pricey fittings, they’re cheaper than continual blunders or the need to change entire plumbing systems to make them compatible. Making a mistake or modifying the system won’t result in having to buy new fittings since the fittings may be reused.
All PEX and CPVC pipes should have their ends cleaned of obstructions. Obtain a razor blade for PEX or sandpaper for CPVC; remove any burrs, nicks, cracks, or damage with each pipe. It is imperative that the pipe end be smooth and finished before being put into the fitting for a proper seal.
When using the push fitting for CPVC pipe, make sure that you press it against the pipe until it can no longer be pushed forward. Pipes made of CPVC are installed first because they are stationary. Push the PEX tube end into the push fitting on the other side of the fitting firmly and fluidly until the fitting is secure. When you turn on the water, check for leaks.
PEX pipes should not be welded, sealed, or attached directly to each other. Use fittings that are labeled “Sharkbite” or “SeaTech” when connecting two of them. If you decide to do any of the above, you should search for fittings labelled “SHARKBITE” or “Seatech”.
What are the steps to connect PEX to PEX?
- The PEX tubing must be removed from the flashing.
- The PEX crimp ring should extend two inches beyond the end of the tube.
- Make sure the PEX fitting is firmly connected to the PEX tube until the shoulder touches it.
- 1/4 inch to 1/8 inch from the end of the PEX tubing is the crimp ring’s position.
- Open the jaws with the PEX crimp tool.
What is the best way to fix a leak in a PEX pipe?
It’s done as follows:
- Using the PEX tubing cutter, remove the damaged/leaking section of PEX tube.
- As part of preparing a new piece of PEX tubing, prepare a piece that is slightly longer than the length of a new PEX tube required to handle the repair.
- Connect the tube to the fitting by using the Crimp Connection Method, and then use the Go-No-Go gage to make sure the connection is tight.
PEX plumbing line fittings commonly require crimping the tubing onto the fittings using a special tool. Solvent-based glue is used to affix CPVC pipe connections to the fittings and pipes. PEX tube will be softened by the solvent-based glue, and the connection will not hold together.