Upon arrival, it was explained that the shower when used at night was not getting hot and staying hot. These issues were happening intermittently after confirming the water heater was making hot water and holding a consistent temperature. I performed a crossover test and narrowed the issue down to the shower that was having the issue. After her approval, I removed the shower cartridge in order to identify what model it was. I will need to contact the manufacturer in order to find and verify a replacement. I am leaving an estimate for replacement of the shower valve in the event that we cannot locate the cartridge and replaced the cartridge.