Replacing a shower valve

[ThisIsNotALoveSong]

Hi there , hope someone can help with some basic questions.

Long story short: Water getting behind tiles in shower, removed tiles to find black mould. A few YouTube tutorials later figured I could probably do this myself even if I have to pay someone to do the tiling.
The shower valve has been dripping water for quite some time and although this wasn't the cause of the damage it seems like the time to repair or replace it.
the valve is concealed. Replacement parts looked more expensive than a whole new unit so I bought a whole new one and intend to fit it.
I have a few questions;

the new valve has parts you can access and clean by removing the plate. (diagram attached) I just want to double check that when tiling we cut out a hole so all the valve is accessible on removing the plate. The previous one just had two holes in the tiles for the taps to stick though

.

Do I need to use ptfe tape ? and where. The instructions just say 'Ensure the inlet and outlet are connected to their corresponding pipework correctly and with necessary sealant'. The existing connections seem to have something.


Do you have any tips ? spot anything i'm missing ? are the existing fittings the correct size for the new unit ? before taking off the old one I want to be sure the new one will fit as I will need to turn the water back on for this evening




Many thanks for any help.

would it be easier to track down and fit new valve cartridges in the one that's there already ?

 

[terryplumb]

Yes ,hole in tile to allow full access.
You could fit two isolation valves to pipework ,that would allow you to turn on house water ,and work on shower as and when you wish.
Compression fittings don't need PTFE tape or sealant.
Fittings that thread into each other need the threads sealing ,with PTFE tape and a thread sealant such as LSX ( other methods and sealants are available and do the same job)

 

[ThisIsNotALoveSong]

thank you Terry.

I did think about fitting isolation valves but it would just be one more thing for me to stress about .
I was planning on using the existing fittings onto the new shower valve. This is ok isn't it? I dont need to use new ones do I ? Assuming its ok to do so is there a recommended way to clean the fittings? I'm guessing there will be old tape and sealant stuck on them?