Can the Dadanco FM units be used for gravity heating?
Yes. Gravity heating is the name given to the heating achieved by circulating hot water through the unit coil at night and weekends, with the primary air system shut down. This is a common and standard design requirement in North America and Europe for induction terminal unit systems.

	Automatic control action at the induction units must be reversed, or bypassed, if heating is to be possible at night.
	The secondary water circuit should include a heat exchanger to warm the water when necessary.
	Tight shut-off valves must be used to prevent warm water entering the primary circuit at night.
	The heat in the secondary system must be dissipated in the morning the plant returns to normal weekly operation, before the refrigeration plant can be allowed to start chilling the primary water.

Is the gravity heating performance of the coil in the terminal unit affected by whether it is vertical or angled? 
Yes, but not by much. For two units with identical coils operating under the same conditions, the unit with the angled coil will provide about 3% more heating output.