For this job I came to see why hot water was taking long to reach upstairs bath, it never got fully hot, it was going back in forth between warm and cold. After inspecting water heater I noticed a recently installed check valve was installed backwards allowing cold water to go back in through the circulation line. I removed the check valves and installed properly. Water was fully getting hot and staying hot in the bathroom after correction was made. I also noticed house water pressure was above 80 psi which is the maximum allowed. Psi was at above 110. I replaced the pressure regulator and installed a higher grade regulator and set the pressure to 65. I tested and left work area clean.