hot water heater trouble

[bignose]

I checked for blockage and there was none that I could see and it's a natural gas heater.
I'm not sure what going on because it quit working again. I had to use the shower last so I found out that the heater wasn't working the cold way. Going snowboarding today so I'm going to deal with this when I get home.

[Cal_stir]

no, the FV sensor senses the pressence of flammable vapours, a flame sensor is a metal rod that will produce a voltage when heated, detecting a flame