What can cause boiler to not heat water properly?

Jeepers_Creepers

I've never seen any warnings about mixing different brands. I certainly have...

The last one I tried - tho' no idea if it's any better than others - is a combined additive from Fernox - inhibitor and long-term cleaner/filter-aid. Got it from SF https://www.screwfix.com/p/fernox-62234-central-heating-filter-fluid-protector-500ml/7917r

Jeepers_Creepers

JustAnotherSaver said:

Jeepers_Creepers said:

The pipe to check outside is the 15mm copper one, not the 22mm plastic.

Will it definitely be those two?

Can you ID these two pipes on the outside wall near where your boiler is located? Cool. The one to rubber-band a small clear bag over is the 15mm copper pipe. This pipe should either be pointing at the ground, or else be bent back facing the wall.

JustAnotherSaver

Opened up the Micro Magnaclean today.

Looked at the pipes connecting in to the boiler. Noticed one of them was wet. Condensation i hope? Felt cold.

5th one from the left. Or easier - 3rd one from right.

@Jeepers_Creepers?