Is the water heater running on natural gas or propane?
propane pressure is affected by the cold.

could have been with the extreme cold in Edmonton might of had a ice build up blocking part of the exhaust vent.

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.

the water heater must have a flame sensor, it must be part of the hot surface igniter therefore not shown on the parts list,, located at the bottom of the heater beside the burner, it should be a rod a couple inches long that will be hit by the burner flame when the burner is lit, that will be need to be cleaned with some sandpaper.

What do mean by vacation mode? I agree that a o smith gas valves are junk, but resetting temperature is not something they do. The LEDs are telling you a code, that code should be in the book. Start there. Here's a manual for the GDP

winged fish thanks for the link.

The heater has started again since I was gone but if I remember correctly it was error 6. This is the quote from the file for the code.

"Ignition/flame failure.
The gas control valve has reached the maximum number or retries (3) for ignition and is currently locked out for one hour.
Cycle the power to the water heater off and on to reset.
1 Gas supply is turned off - pressure is too low.
2 Ensure the flame sensor is clean - use fine steel wool to clean the flame sensor.
3 Manifold gas pressure to the burner is too low.
4 Check igniter assembly plug and the socket on the bottom of the gas control valve for good connection. Replace igniter assembly if the plug is worn or damaged replace the gas control valve if socket is worn or damaged.
5 Replace igniter assembly.

If it is in fact that code, then dimes to dollars it will come back soon and you need to clean the flame sensor. Do yourself a favor, if it has the torx screws on the cover, take them out and chuck them as far as you can. Replace them with something a normal person will have a driver for.