I have mixer taps throughout my property, however, the mixer tap on my bath (hot tap) constantly runs lukewarm. Why is this? All the other mixer taps runs very very hot. Very frustrating as having a bath is a no go. Help!

Shut the water off to the valve and open it up. Remove the cartridge and check and clean the inlet ports. Now place a pan over the valve and turn the water back on for a minute to flush out the supplies, Reassemble and test, Better now? Good luck, Tom

Before proceeding as Tom suggested I would first check to see if there is a MIXING or TEMPERING valve that is solely dedicated to that particular tub. Otherwise, look under the mixer tap trim and see if there is a TEMPERATURE LIMITING DEVICE (something with notches or a screw).

If you do not find any of these, proceed as Tom stated.

Mark