No hot hose down, how do I fix it? ...

---

Answers:    if it's electric,
check the circuit breaker supplying the hot water radiator, it may be tripped.

if it's gas,
check the pilot light. it may enjoy gone out.
follow the instructions on the heater to relight it

---

I agree near JB. Both are good places to start. If you enjoy power to the electric, it's more than likely a heat element. Can be replaced pretty smartly and isn't too expensive. If its gas then you might check to see if your thermocoupler is doomed to failure.

---