By reading the directions provided with the heater
The older types of water heaters have a gas controller that has on top there is a button called pilot and you must turn the adjusting knob to pilot then hold the button down , light the pilot tube located just below the thermo couple HOLD it down for TWO minutes (enough time to heat the thermo couple) then release and make sure the pilot stays lit.. Then turn the dial to ON and adjust the temperature
On the newer models there is an sparker and you should read the directions supplied with each type of heater .
YOU should also find out WHY THE PILOT LIGHT WENT OUT as sown drafts can be quite dangerous
You turn the regulator to OFF, wait 2 minutes, then turn it to 'Pilot' and depress it. Have a long match as is used for BBQ's , reach in and hold match where flame shield is around pilot. It should light immediately, BUT keep holding the button depressed for 2 minutes. If it goes out when you release the button then you have a problem with the thermocouple and the easy solution is to change it.
Your appliance might have a built in piezo ignition (spark), if so there is no need to use a match. Follow the steps above, not using a match and you should press the "spark" button to light the flame. You should hear a click, click sound from the spark, then after about a minute, release the button and turn it to 'ON' - you should now hear a whoosh as the gas ignites. Keep your face away from the appliance for safety reasons.
Gas water heater has an orifice for main burner and for pilot light, if not electronic ignition.
No because water heaters have a safety valves and when the pilot light goes out the safety valve shuts off the gas
small amount
THERMOCOUPLE or defective gas valve
because its leaking out gas
Same as any hot water heater. Turn the gas valve to off.
Gas not turned on to water heater. Gas valve on water heater not set to pilot setting. Faulty gas valve. Igniter for lighting pilot not working.
If it is gas operated, the hot water heater may not light because it may have a defective millivolt sensor. The millivolt sensor is heated up by the pilot and generates a fractional amount of voltage telling the gas valve that the pilot is lit and the gas valve can now be safely opened to heat the water heater.
A small amount to keep the pilot light going.
low back, spillage, or a bad thermocouple.
No, it is not dangerous. (Unless you are working with a water heater that is 20+ years old.) In any modern hot water heater, if the pilot light goes out a fail-safe will go off - preventing gas from leaking out. Also, there is a sensor so if there is not enough air-flow or oxygen with the water heater, it will shut off the gas.
When pilot light goes out, gas flows out of the pilot light nozzle. If out has continued for a long time, a gas cloud can develop around the furnace. When you go to light the pilot light, you'll ignite this gas cloud and make a big fire ball. If your basement is drafty, you might never get a huge cloud of gas hovering around your furnace. When you notice that your pilot light is out, you should shut off the gas to the furnace and allow any stray gas to dissipate before you turn the gas back on and light the pilot light. alliedallcityinc.com