Facepalm: If there’s one problem you don’t want in your CPU cooler, it’s an inability to keep the processor cool. Sadly for manufacturer Fractal Design, such an issue has been identified in six models of its All-In-One watercoolers, the result of a manufacturing flaw.

Fractal Design says that following user reports of an increase in CPU temperatures, it has halted sales of its Lumen AIO-series watercoolers and is issuing a voluntary recall. The company writes (via Hot Hardware) that the temperature spike is caused by soldering material used in the aluminum radiator, as well as impurities introduced during manufacturing.

One or both of these issues can cause a reaction with the chemical composition of the coolant, which can lead to sediment build-up that gets caught in the fins of the CPU block. The resulting blockage causes the processor temperatures to rise.

As with many of life’s problems, ignoring this one can make things worse. Allowing the blockage to build up further could affect the function of the pump and impede the water flow to a point where computer failsafe mechanisms are triggered, potentially throttling CPU performance or shutting down the entire system.

The following Lumen AIO coolers are affected:

• Fractal Design Lumen S24 RGB
• Fractal Design Lumen S24 (non-RGB)
• Fractal Design Lumen S28 RGB
• Fractal Design Lumen S28 (non-RGB)
• Fractal Design Lumen S36 RGB
• Fractal Design Lumen S36 (non-RGB)

Fractal Design emphasizes that none of its Celsius or Celsius+ AIO liquid coolers suffer from the same manufacturing flaw. The company says it will replace any listed models free of charge, even if they aren’t showing any of the problems. Fractal Design adds that the Lumen AIOs don’t have any thermal issues, so they’re still safe to use.

The Fractal Design team is now working on a new version of the Lumen coolers with an updated radiator and a new liquid formula. They’ll be used as replacements for current Lumen owners and should hit distributors and retailers in about six weeks. Owners can fill out this form for a replacement using the serial number on the short side of the radiator and proof of purchase.

This isn’t the first time Fractal Design has had to halt sales of a product. The Torrent PC case launched to rave reviews last year was found to contain Nexus 9P Slim fan hubs damaged during the manufacturing process, potentially causing a short circuit. Owners were told to unplug the fan hub and order a free replacement kit.