With the warmer weather here I decided to unwinterize my coach last night. I fairly new at this as its only the second time I have performed this process. I ran into a problem with my water heater, I attached city water to the coach and put the drain plug back into the water heater. I then switched the bypass valve to the normal position. I then turned on the gas supply and and the heating unit came on as normal, I then waited a few minutes while the water heated up. This is where the problem arrises, the water does not seem to be filling the water heater, I verified this by removing the drain plug and no water came out. The flame also went out on the heater as well, I am guessing this is a safety feature. I am not sure where to look next.