I need some help with my van. When I hook up to mains water, I turn on the hot water switch inside the van next to the red light. I turn on the switch inside the hot water unit (external) and then when I use the hot water, the red hot water light comes on and won't turn off. Is this normal? Am I doing something wrong? Then also, some times the pump doesn't shut off. I will turn the switch off and then on again and then it shuts itself off. Any help for this novice?