Faulty Thermostatic Shower Cartridge? Read this Guide Now…

Is your Shower running hot and cold? – A Faulty Thermostatic cartridge could be the reason behind this…


Signs of a failed thermostatic cartridge in your shower:

  • Piping hot water despite the choosing cold on the temperature control dial
  • Stiff control dial when adjusting temperature
  • Intermittent hot and cold water
  • Water going hot then cold and back to cold etc.
  • So in summary basically the inability to regulate the temperature of the water using the control dial on the shower


Causes of a failed thermostatic cartridge:

  • An imbalance of pressure between mains cold water and the heated hot water from the shower the heated hot water. This imbalance will cause damage to the cartridge in its housing
  • Dirt or grit from the mains water entering the system can cause damage
  • Hard water limescale build up can cause the cartridge to lose its mobility and seize up

Types of Thermostatic Cartridges:

  • Type 6 – Screw fit, easily identified by the flat head screw thread to the top of the cartridge
  • Type 8 – Same as above
  • Type 12 – Not so popular, secured by grub screw however wider than the others
  • We have a wide selection of thermostatic cartridges featured on our website with in depth reviews. Click here to view these

How to Install Thermostatic Cartridge:

  • Remove shower face plate, ensure you are keep all screws you remove during this process for refitting later
  • Once the shower plate is removed you should see a hole in the wall where a shower valve is located. Isolate the water at this valve
  • Once you have exposed the thermostatic valve mechanism you can unscrew if using the appropriate tools for the valve
  • Refit the new thermostatic valve
  • Turn water back on at isolation valve
  • Refit shower plate and test

For a good video on how to install a thermostatic cartridge see below:

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