if you suddenly lose hot water and heat. you may want to try doing this!

magically happens. make sure you follow instructions:

1) turn the dial to off.
2) make sure your heater gauge is set to vacation or lowest setting possible.
3) let it sit for 10 minutes to let leftover gas evaporate? you dont want to explode.
4) turn the dial to pilot
5) and press the red button(can be black for reset). keep holding it
6) while pressing igniter.
7) you will see sparks, and pilot light will come on.
8) GENTLY! turn the heater gauge to warmer setting while enjoy a little burst of gas.

that should do it.
cheers!