First of all I would like to say that I have not tried to negotiate with the supplier of this gauge. I'm sure they would work with me. The sensor didn't work out of the box. I usually buy locally but there was no time to wait. I installed a pressure gauge, opened the check valve and the pressure gauge read an unexpected pressure. I closed the shut-off valve and tapped the pressure gauge. The pressure rose, I removed the pressure gauge and since there was pipe grease on the threads I threw it away.