Hot Water

Hot Water
We stopped getting hot water in all our showers but not our faucets? Why?

All of a sudden all of our showers stopped producing hot water. It is not ice cold, but it is also not hot either. This is happening to all our showers. But we can get plenty of hot water from our faucets. The plumber who came out wants to replace the cartridges in the showers that regulate the hot and cold - but this doesn't make sense that all of the cartridges in all of our showers would suddenly all go bad at the same time. So what else could be causing just our showers to no longer get hot water?

there two thing that i would do in your showers. 1 is pull the hand off to see if you have a justment for the hot water side some faults have them for summer and water temp. you move it in or out for hot water. then2 is the shut off valve for the hot water to see if it open or not and there nothing stoping the watergoing through it. start there and you will get it . if it was you tank you wouldn,t have hot water at the sink faucets.