This is underneath our immersion heater. Looks like a water filter. Should I be replacing whatever is in these plastic containers?
Yes, water filtration/purification system, one (on the left?) Is a particulate filter and the other is a probably a carbon filter. They do have a limited life so the filters inside should be replaced.
Thanks. I assume I can get them in Leroy merlin or the brico.
Most of those Brico places will sell them, but have a look at prices on Amazon or ebay. You might find there is a saving to be made.
Yours still look to have life in them…as crystals still look greenish and left one is perhaps still looking clean? Depending on your water you need to change them every 6-18 months. Not cheap, about 25€ a pair. I’m not convinced they make a huge difference, so we don’t change them very often…
These are ours, but see if you can find a brand name as not all cartridges fit all holders as we learnt to our cost (despite what sales assistant said!)
I think ours may have been turned off from water so will try them turned on.
From the valve positions in your photo, the filters are “on” - the “by-pass” valve above is closed