I'm sure im preaching to the converted but just a reminder that the low pressure tier goes up to 75mb and it is quite possible to see elevated pressures on low pressure services so if you use a water guage, you may well find that the water disappears over your shoulder when you turn the ECV on. I visited a job recently where a GSR undertaking work was perturbed at the seemingly high pressure. He only had a 12" WG and thought the regulator was faulty. There was close to 50mb on the service. The important things of course are that the ECV doesnt let by,the regulator locks up and that it regulates when gas is flowing.