its already running???
It sounds like you did something right. I think your pressure and w.c. setting are set by regulator attached to side or inside of heater. No gas appliances are hooked up direct to line, and regulators are typically provided with unit. all regulators are set to work on your nat gas pressure in your home, or l.p. if thats what you have. So everything should be fine, if it is not working properly please post the exact nature of your problem, maybe we can help more. By the way, you should check your new gas line by isolating it from existing system and charging with exactly 15 p.s.i. no more no less. If it holds this for 10 hrs. or more your line is safe.