No hot water

Need some advice. Have an oil fired buderus boiler and an indirect dhw tank. System has been acting funny with zone panel set on hot water priority. So I shut that off and hot water would run out but would recover fairly quickly. Now tonight, no hot water. Any thoughts?? Thanks

Depends on what you mean by "acting funny". Even with priority off it should still heat the tank when the tank is calling for heat. If the aquastat on the indirect (or it's wiring connections) are flaky, or those of it's zone pump, you could have intermittent performance, eventually leading to none. But a better description of the "funny" behavior might provide more insights.