Red SPP Furnace tune up on system we just installed this year. This is a rent house. Renter was having trouble getting hot water, so looked at HWT and found what looked to be a bad thermocouple, the pilot was lighting but not staying lit when turning the gas valve to hot water stages. Offered to replace thermocouple and flush hot water tank with today’s service, and customer agreed to have thermocoupler replaced. Started with hvac equipment. Changed filter included with red club. Checked flame sensor and it is brand new. Checked flue, evaporator coil, drain and blower. Cycled system in all stages and it is running great according to manufacturer specifications. Checked electrical amps and ohms, checked heat rise and delta t. Hvac system is working well. After opening up and removing old thermocouple in hwt, found it to be a different size than the universal kits we use for furnaces and hot water tanks. Unit is a 2012 Bradford White. The pilot light is lighting, but not staying li