shower mixer valve

[stucky]

hi does shower go hot when heating is on.and also can you reduce cold supply to shower with an iso valve as cold controls temp.

 

[quickfit]

hi all, for some strange reason if i turn the hot tap on at the side of the shower cubical and leave it running the water coming out of the shower mixer valve is hot, i can only think it being the thermostat cartridge in the mixer being in u/s, because with this happening i now know the boiler is ok and that there is no blockage to the mixer valve via the hot water supply, so can somebody tell me what to remove from the cartridge so that i can have a supply of hot water running through the mixer, i know that removing the thermostat that the hot water isn`t controlled but with a bit of practice i can regulate it with the cold to prevent getting scalded, i have in the past removed some bits from another cartridge which was installed but i think i removed not enough bits because it made no difference ,cheers, mick