pilot light on unit is to small and not hiting thermocouple correctly,due to jet partly blocked removed jet and clean,not with pin or the like as you can oversize jet but with air spray or place in water removed and with lungs full blow through hard,but jet upto light and you should see through replace light pilot
when you first light may flicker for 12 secs until water dried out of jet
tony...tsp heating, July 2007
