Has Your Thermostatic Cartridge Failed? – Read our Guide

One of the most common parts to fail on a steam shower, shower cabin or steam shower bath, particularly on older models is the thermostatic cartridge.

Symptoms Include:

  • Unable to regulate the water temperature
  • Only cold or warm water
  • Only scorching hot water
  • Stiffness in dial when adjusting

If you are unable to regulate the temperature and you are getting only cold/warm water or conversely very hot water from your shower, it is an indication that the thermostatic cartridge has either failed, or is failing. Another symptom can be recognised by stiffness in the knob when you try to adjust the temperature.

Why Has the thermostatic cartridge failed?

There are several reasons why the cartridge may have failed; the number one cause is an in-balance in water pressure between the mains cold pressure and the heated hot water(and this is very common). This constant in-balance between the two will cause damage to the cartridge which is housed within the valve. Fitting a PEV (Pressure Equalising Valve) can resolve this. Note it will not fix an already failed cartridge.

Another reason could be down to muck in the system, perhaps the plumber used flux to solder pipe work and this wasn’t flushed through, again due to the delicate nature of thermostatic cartridges, the debris can damage the part.

Hard lime scale build up is another cause for the cartridge to fail. So if you live in a hard water area, it certainly pays to install a softener, these are not always expensive at people think, and a simple inline device like the Scale Wizard will drastically reduce the build-up of calcium deposits. Not only that it will assist in keeping you cabin glass cleaner as well as furring up of the hand shower, hydro jets and monsoon and most importantly the Steam Generator if you have a model fitted with this feature.

Replacing a Thermostatic Cartridge

To replace the failed thermostatic cartridge is not a difficult task, all the work is done from inside the cabin, so moving the whole unit out is not necessary. We have put together an easy to follow how to guide here.

What Thermostatic Cartridge type do I need?

Unfortunately in most cases even if you know what brand and model of steam or shower cabin you have it will not help us to advise which type you need, over the years models are fitted with varying types of valves. These valves generally house one of two different types, although there are a couple of other types that we will explain further down. The good news is we have a few brands that we can confirm which model you will need.

What Thermostatic Cartridge Do I need for an Insignia Steam Shower or Shower Cabin?

The insignia range of showers and shower cabins are fitted with this model here, and whilst the appearance may differ from your existing cartridge it will fit.

What Thermostatic Cartridge Do I need for an Aqualusso Opus or Alto  Steam Shower or Shower Cabin?

The Aquausso range of showers and shower cabins are fitted with this model here, and whilst the appearance may differ from your existing cartridge it will fit.

Type 8 – This is a screw fit type – The most popular by far, easy to identify by the screw thread to the top part of the cartridge, you will also be aware that you had to screw it out of the valve housing when removing.

You have the option of purchasing the Type 8 Vernet cartridge; this is a branded cartridge and is fitted with a wax sensor, proven to be far more reliable and efficient than the regular type. Brands such as Vidalux, Lisna Waters, Superior Saps, Aqualine and Aquaplus now fit these as standard to most new steam and shower models these days.

Type 6 – This is a push fit type – The second most popular type , again easy to identify as this pushes into the shower valve housing, you would also be aware that you had to remove a small grub screw from the underside of the housing when removing.

Same as the Type 8 above you have the option of purchasing the branded Vernet Type 6.

Other types include the Colorspa Cartridge. If you have a Colorspa steam or shower cabin then this is the only cartridge that will fit your shower valve.

Type 12, fairly uncommon, these are very similar to the type 6 in that, in that it is secured into the housing by way of a grub screw, but you will notice the gauze section is much wider.

With models such as the Type 6 and Type 8 where you need to also replace the plastic temperature safety lock please visit the thermostatic cartridge page of our store

Don’t forget to download the easy to follow document showing you how to remove the tool below.

If you still need some assistance, simply remove the existing cartridge by following the instructions from the above link and send us your photo via our Whatsapp link or email link on our contact page