There was a code 10 on Bradford white water heater. Contacted customer support and they instructed me to clean off the NOx RTD sensor for water heater. Cleaned off sensor and re connected. Turned water heater back on and everything was working properly. Water heater is still under warranty so explained to customer if they continue to have this code pop up then we will need to replace the sensor part number 45-49785-00. Further inspecting of water heater I found customer had a circulating pump that is not set on a timer. Strongly urged customer to have timer installed in order to prevent pump from running 24/7 which will wear out water lines much faster.