What should I beware of when installing an air to water system?

Concerning the refrigerant circuit are applied all installation rules of a usual air conditioning unit. Concerning the water circuit, apart from the proper connection of the water piping (welding, quality of the materials and parts etc), you should also check if all the needed parts in the system have been installed properly (buffer tank, expansion tank, safety valves, flow switch, circulator, filter, power switch, temperature sensors etc), in order the unit to operate with safety and with the higher efficiency.