Plant mode

During normal operation, the air handling unit control strategy will control the fan speed.
The input "PlantMode" input from the control strategy module is decoded to provide the required fan speed signal. The table below shows fan overrides depending on the "PlantMode".

Notes:

Fire overrides have the highest priority over plant mode overrides.


Plant mode

Stage1Cmd

0 = off

off

1 = optimum start

auto

2 = night cycle

auto

3 = night purge

auto

4 = occupied period

auto

5 = extended operation

auto

6 = delayed switch off

auto



11 = duty cycling

off



20 = frost protection

off

21 = fan failure

off



30 = fire override

off