I have a plumbing question I'm sure someone in here can answer. This weekend I had to drain the water in the hot water system. (moving one baseboard around) To speed up the refill process I tried lifting the lever on the water pressure regulator. Just a few inches beyond the water pressure regulator is a water pressure relief valve. When I manually opened the regulator the city pressure trips the relief valve and water dumps. To me this seems to work like it should because each part seems to be doing what it is intended to do. Boiler is a Slant Fin about 15 years old. I could create a bypass loop with two valves that isolate the higher pressure off the pressure relief valve momentarily. Would a bypass loop be the way to introduce city pressure for quick filling ( two stories with old style large water heaters). Is the inline water pressure relief valve absolutely necessary ; would the pressure valve built into the boiler pick up the excess water pressure should the inline regulator fail? Hope I've given enough info here and thanks in advance.