The Shower Doctor Surgery: How to replace an Aqualisa c

When it comes to servicing your Aqualisa shower, very little has changed over the last 30 or so years. Although the knobs on the front can look very different, this is just a case of the manufacturer ensuring the unit continues to look modern. Once you remove the casing, the models pretty much remain unchanged since the 80s. Here's a brief guide to help you swap your old Aqualisa cartridge for a new one.


You'll need a couple of things to complete this job:


In addition to this, you should prepare your bathroom as you would in the usual manner to make sure you don't misplace any small screws - cover the plughole so they don't end up disappearing! Finally, turn your water off.

Removing the cartridge

The external covers and knobs can be removed relatively easily by simply pulling them off. Depending on the particular model, you may need to use your flat screwdriver here as a lever to prise them away from the valve. One exception to the 'they all pull off' rule is one insert that is white and has slight grooves on either side - you'll need to unscrew this one.

After removing the on/off knob by pulling it forward, you now need to take off the temperature control lever. This is held on by four Pozidriv screws that come out quite easily.

Most popular Aqualisa mixer cartridges.
3 of the most popular Aqualisa thermostatic cartridges: High Pressure (green), Gravity/Pumped (grey), and Combi Boiler (pink).


Now we come to the cartridge itself. Remove it using your Torx T25-bit screwdriver, making sure to unscrew it evenly so that it disengages from the valve smoothly. After removing it, you might wish to consider replacing an O-ring, which is right at the back of the valve. While this isn't essential, if the cartridge doesn't work after you've replaced it, the first thing we'll suggest is to swap the O-ring out - so you could be saving yourself time and money by doing it while you've got easier access to it. The ring itself can be quite tricky to remove, and this is where your crochet hook comes in handy to effectively fish it out of the small hole in the back of the valve.

Replacing the cartridge

If you've taken out the O-ring, then you obviously need to put your new one in first - although this is somewhat of a delicate procedure. The best approach is to balance it on a small screwdriver and use this to try to place the ring back where its replacement came from.

When putting the new cartridge in, make sure there's a new gasket on it. Once everything's as it should be, screw the cartridge into the valve - although be wary if you've got an older model that you might be using brass inserts to do this. If this is the case, you should make sure you don't screw them in too tightly, as this could cause them to split - something that could cause you quite a headache! Just as you did when unscrewing the cartridge, make sure the screws are tightened evenly so the unit is drawn in carefully.

Next to go back on is the temperature control lever. It's worth noting here that on the right-hand side there will be a series of holes running from 12 o'clock to six o'clock on the valve. These are for temperature limit pins - so if you want to stop your shower from getting too got, pop a pin in the corresponding hole.

Finally, place an O-ring around the spindle on the temperature control knob and push the control box back on. Consider your shower now serviced!

If you want further details, check out our DIY video on this topic (or scroll below to watch it here).

Full video:

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