big russ wrote:
hohenwald48 wrote:
big russ wrote:
WyoTraveler wrote:
Watch the ignighter while your wife throws the switch. Are you getting spark? I'm not sure, maybe there is a reset if the tank gets too hot.
it has what seemed like two reset buttons ,it didn't work.what ignites he gas and how does it know when to ignite?
The gas is ignited by a spark generated by the control board when the thermostat says the water is cool. The control first opens the electric gas valve then generates the spark. It then monitors the flame (via thermocouple) to insure it has lit. If it has not, it will shut off the gas valve.
ok switch on control panel is on, LED indicator light is off., I have gas.its not firing .what could cause it to not fire after firing it on a dry tank?
There are basically two thermostats in the system. One that operates the control board on a regular basis. I don't know exactly but lets say it's set at 130 degrees. As you use water the tank cools and the thermostat closes allowing voltage to the control board and igniting the gas. As the water heats it opens at 130 degrees shutting off the flow of gas. This cycle continues over and over as you use the hot water.
The second "thermostat" is a safety device that operates only in the event of a failure of the first thermostat to turn off the gas when the water reaches 130 degrees. This second "thermostat" is also called a "limit switch" or "high limit". It is designed to open at say 140 degrees. Once it opens it will never close again and must be replaced. Some WHs have a resettable high limit but most do not.
As I said, I'm just using examples of the temperature setting of the thermostat and high limit. I don't know what the exact settings are. However, the high limit setting will always be higher than the thermostat setting.
The LED indicator is a fault light. If it is off that means the control board has not detected a failure to light fault after calling for the burner to light.
The electric operation of the WH is controlled by a separate set of thermostats and high limit switches. For control purposes there is no connection between the gas and electric operation.
Keep in mind that I am speaking in general terms. There may be WHs out there that operate completely different from what I've described.
