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Do you have the water heater bypass on? That is the most common reason for having hot water in the tank, but not in the fixtures. Most are located on the rear of the water heater, UNLESS they have a valve marked for that in a compartment. See if that might be the case here and get back to me if you need more as all follow ups are included in our fee. I can tell you about the valve(s) if that isn't clear. Attach a photo of yours to your post if you can. Some are one valve or two or three.............depending on who made them.
What is the make and model of your water heater? Are you sure it is coming on?
Open up the outside inspection cover and it should be visible on the data tag...........
IF this is an Atwood XT model or the same version of a Surburban water heater the flow valve may be plugged up with calcium sediment. It can be taken off and cleaned as a rule or in severe cases it has to be replaced, but those are pretty expensive so cleaning it is always the first option.
If you Bookmark this you can come back to it later at a more convenient time. Once I have the make and model of your water heater we can sort this out pretty quickly.