Download november 2008 rego answers there all in there. First one is

4)
The number of occupants
The activity of the occupants
Whether dust or fumes must be removed
Legislative requirements

6)

An instantaneous system has no storage capacity but uses a heat exchanger to transfer
heat energy to the water as it flows through the water heater.

An indirect system utilizes heat produced by a separate process and passing this through
a sealed coil or heat exchanger immersed in a body of water. The heat is transferred to
the body of stored water ready for discharge off.