Arrived onsite customers boiler has stopped working since we were out roughly 12 days ago. Error code states that the boiler is over heating. Contacted tech support. Tech support walked me through diagnosing a bad diverter valve on the inside of the triangle tube. He stated that the valve is sticking internally, that is not allowing much flow to get through. The customer informed me that the domestic hot water is starting out hot than runs cold after running the hot water brought this up to tech support and he explained that this would happen if this diverter valve is sticking. Oct, 22, 2021 Arrived onsite to perform the installation of the new diverter valve. Began by isolating the system. Turned off power. Drained system as required. Provided and installed a new OEM diverter valve. Followed manufacturers instructions step by step. Restored water and power to the boiler bleeding air as required. Found no leaks present. System would heat up to the correct temperature on the supply