Softener position in the supply line
Install the water softener on the main cold water supply line after the pressure reducing valve (PRV) and before the cold water supply to the Bradford White water heater. This sequence: meter -- PRV -- softener -- Bradford White cold inlet. The softener must be installed after the PRV to operate within its rated pressure range (typically 20-80 PSI). Installing before the PRV exposes the softener to full street pressure, which can exceed softener specifications and damage the control valve.
Thermal expansion tank requirement
When a water softener (or any point-of-entry device with a check valve) is installed upstream of a Bradford White storage water heater in a closed plumbing system, thermal expansion from the water heater creates elevated pressure in the system. Bradford White requires an expansion tank on the cold inlet side of the water heater in closed systems. The expansion tank must be sized per ASME guidelines based on system volume and supply pressure. A 2-gallon expansion tank is appropriate for most residential Bradford White installations. Failure to install an expansion tank in a closed system causes pressure cycling that stresses the Bradford White tank fittings and T&P valve.
Flush procedure after softener installation
After softener installation and before reconnecting the Bradford White water heater: (1) Open cold water taps throughout the home. (2) Open the softener bypass valve and run cold water until the line is clear. (3) Switch the softener to service mode and run again until the outlet tests 0-3 GPG. (4) Reconnect the Bradford White cold inlet. (5) Fill the water heater tank with softened supply water per Bradford White startup instructions. (6) Test the outlet hot water hardness -- it should match the cold water softener output within 1 GPG. If the hot water tests significantly harder than the cold, the softener is not correctly set up, or the bypass valve is partially open.