Shower an lack of hot water

[RadarBailey]

I have a shower mixer. The water is fed by a cold water tank in the loft and a hot water by a cylinder. If there's a problem with the cartridge what do I look for. There just doesn't seem to be enough hot water coming through the system

Thanks

 

[TicklyT]

Is it a new shower, or one that has worked satisfactorily in the past?

Is your boiler heating the hot water to a high enough temperature?

There is often a stop pin behind the temperature control which can be moved to select a higher temperature. They are put there to reduce the risk of scalding by selecting too high a temperature, but they are not always set accurately.

After a period of use, some valves seem to stick at whatever is the most frequently used setting. Some manufacturers recommend moving the temperature control all the way from cold to hot several times about once a month to keep everything working as it should.