Your heating is working, but you have no hot water. If you live in a building with multiple tenants in and you share the use of the boiler, it may be that the tank is empty because others have used the shower before you. If this is not the case, you can reset the boiler in various ways.
If the above doesn’t resolve the problem, we advise you to check the shower or the hot water tap. Is there a lot of lime scale on it? This may be the reason that you don’t have hot water. A calcified showerhead or aerator gives too much back pressure to the heater whereby it doesn’t start.
Descaling is the responsibility of the tenant. You can buy a descaling product from any good supermarket or a hardware store.