How to Replace a Thermostatic Shower Valve Yourself

A thermostatic shower valve replacement is easy if you have a few tools and are familiar with plumbing. We'll walk you through how to replace an exposed shower valve in this article.

Hidden shower valves hidden behind walls or tiles will be more complex and out of the scope of this article. It might be worth calling a professional.

1. Make sure you do your checks

Most thermostatic shower valves can be installed in a standard manner and with standard measurements. If your valve passes these checks, you can move on to the next step. If your valve fails to pass these checks, you can continue the job, but it may not be as simple. In this case, it is worth calling a plumber.

This is what you should do:

• The hot water supply is to the left, and the cold water supply is to the right
• Your valve connectors' centres are spaced at 150mm
• The distance from the wall to your connectors' front is approximately 35-40mm

2. Turn off the water

It is dangerous to begin removing and dismantling items before the water has stopped flowing in your shower.

You will find some isolation valves to control the hot and cold water supply that feed your shower valve. Please turn off the hot and cold water supply to your shower valve by finding them. If you don’t have isolation valves or can’t locate them, then shut off the main water supply at the stopcock.

3. Remove existing pipework

The new thermostatic shower valve may come with a solid riser pipe. If your existing shower has one, you will need to remove it.

Riser pipes are usually attached to the wall using a few brackets. To remove the pipe, you can unbolt the bracket. You may not be able to see the screws at first, but they might be hiding behind a small plate you can easily pop off.

4. Remove the existing shower valve

Now you can remove the old shower valve. You will see two large nuts attaching the valve to the feeds if you look at both the hot and the cold feeds. While holding the shower valve, undo both nuts. This will allow it to be pushed away from the wall without hitting the floor.

The covers can be removed from the supply pipes, and any dirt or grime will be cleaned off the wall.

5. Flush out the pipes

To flush out any debris or dirt that may have built up, running water through exposed pipes is a good idea. Turn on the water again, and let the cold and hot feeds run for a few seconds.

Depending on where your isolation valves and stopcock are located, it might be easier to have someone else help you. To catch the water and prevent any mess, you might want to use a bucket.

6. Install the new shower mixer valve

First, cover the supply pipes with the new covers. The covers should be screwed on and tightened to fit flush against the wall. If you need to ensure they are level, adjust them. You can also use a spirit level to check.

You should attach the seals or filters to the valve's back. Once the seals have been installed, you can press down on the valve and tighten each nut. The nuts should be tight enough to secure the valve against the wall. However, it would help if you did not tighten the nuts too tight, which could damage the waterproof seals. You should ensure that the valve is correctly positioned and that the hot side of the valve is facing the cold side.

7. Install brackets and riser pipes

You should be able to use the same holes to attach your brackets and riser pipes to the wall. You will likely be able to use the same holes for your riser pipe sizes. You will need to measure and drill new holes if you don't have the measurements.

Most likely, you will have a diverter valve. This screws into the top body of your new thermostatic mixer valve. Attach the riser pipe to the diverter valve. Screw it up to connect. To ensure that the riser pipe stays in place, screw in the brackets. The new showerhead can be attached to the riser pipe. Attach the body wash attachment to the showerhead.

8. Check your shower valve and tap

Switch on the shower and turn off the water. Check for leaks around the showerhead or valve. You might find small leaks around the valve or showerhead. Once this is done, the leaks should stop.

Also, ensure that the water temperature is at least 38 degrees Celsius. This can be done by using a thermometer and keeping it underwater flow. To access the cartridge, you will need to remove the thermostat head if the water temperature is below 38 degrees Celsius. Adjust the cartridge temperature to 38 degrees Celsius by turning on the water. Once you are satisfied with the temperature, replace the thermostat head to start a shower.