Plant mode

During normal operation, the air handling unit control strategy will control the cooling coil.
The input "PlantMode" from the control strategy module is decoded to provide the required cooling valve output signal. The table below shows the cooling coil overrides depending on the plant mode.
Fire overrides have the highest priority over plant mode overrides.


Plant mode

Cooling valve

0 = off

closed

1 = optimum start

auto

2 = night cycle

auto

3 = night purge

closed

4 = occupied period

auto

5 = extended operation

-

6 = delayed switch off

auto



11 = duty cycling

closed



20 = frost protection

closed

21 = fan failure

closed



30 = fire override

closed