Hi all,this is my first post and wondered if anyone can help. I have a problem with my carver water heater on my 1989 globetrotter. When i use it on gas it lights up fine and the panel light stays on green, however after about 30mins there is a small amount of fairly warm (not hot) water then it runs cold.The burner is still on and the water flows fine,it,s just not hot. Could it be a thermostat fault?, Any advice would be helpfull, Thanks