The advantages of flow reversal when descaling and chemical cleaning
During descaling limescale dissolves with the evolution of gas.
The resulting effervescence and foaming can create a barrier which impedes and, in some cases, prevents the descaling chemical from further reaction with the deposits.
Reversing the direction of flow and return with the flow reverser (see diagram) allows the foam and gas to discharge through the tank, eliminating the barrier effect.
Apart from allowing deposits to be attacked from both sides, penetrating and breaking up their structure and speeding the descaling process considerably, flow reversal often enables previously blocked tubes and heat exchangers to be successful descaled.