How do I determine the required size of an expansion tank for a domestic hot water system?

To determine the required size of an expansion tank, you need to calculate the total volume of expansion of the water in the system. This can be done using the formula: ΔV = V x (T2 – T1) / (T1 + 273), where ΔV is the volume of expansion, V is the initial volume of water, T1 is the initial temperature, and T2 is the final temperature. The expansion tank size should be selected based on the calculated volume of expansion, taking into account factors such as the system’s maximum operating pressure and temperature.