PEX tubing is great stuff. Tough, durable and flexible – there’s a reason why it’s made so many inroads against copper pipe.
However, with flexibility there can be a “twist” to PEX. Specifically, when PEX is forced to flex more than it should – whether deliberately or accidentally – it can kink. Some installers will try various tricks to exceed the manufacturers recommended bend radius in order to achieve desired installation outcomes. Most manufacturers do not allow the practice of “hot bending” tubing to make a tighter bend radius. PEX can be easily bent by hand, or with the use of approved bend supports to a radius as small as five times the tubing’s outer diameter. But you want to avoid kinking the tubing.
A kink impedes the flow of water and creates a weak spot in the tubing, so it must be fixed. One way to do this is by applying heat so the tubing softens and regains its original shape. But this repair can be tricky.
The PEX must be heated above its crystalline melting point but not too hot so the tubing isn’t further damaged. A torch is too imprecise and can overheat the material, so a temperature-controlled digital heat gun is the recommended tool. However, it can take several minutes to perform this process correctly, gradually heating all sides of the tubing and then letting the tubing cool down to room temperature, untouched to avoid the risk of the kink redeveloping or additional damage occurring. And once the tubing has been compromised by the initial kink and the heat repair, it’s more likely to kink again in the same spot. Overheating can shorten the life expectancy of the tubing by thermal degradation.
The only sure way to eliminate future problems with kinked PEX is to cut out the damaged section and repair it with a fitting. Not only does that remove the weak spot, but it avoids destroying the physical characteristics of the tubing which make it a great choice to start. Plus, and it can be done in under a minute with Viega’s PureFlow fittings. Cutting out the kink and installing a coupling also retains Viega’s 25-year warranty on PureFlow PEX and the 30-year warranty on Viega Barrier PEX and FostaPex tubing.
Additional considerations to protect the physical characteristics of the tubing would be using sleeves at all penetration points, use only plastic or plastic-coated tubing supports, leave a small amount of slack between fasteners to account for tubing contraction, use suspension clips or an approved plastic insulator where tubing passes through studs or joists where abrasion and noise is a concern, and lastly, use nailing plates to protect the tubing from nails and screws where it passes through studs.
For more information contact our Technical Specialists at techsupport@viega.us.