90
RT-SVX073A-EN
Table 43. Ventilation override mode (continued)
VOM Input OUTPUT OPERATION Heat Cool Mode Status
Mode E
(Purge with Duct Static Pressure
Control)
Supply fan On/Duct Static Pressure Control Fan Only
Outdoor air damper Open
Relief fan / Relief damper On/Open
Return Fan/Relief Damper On/Open
VAV Box Relay Energized
(a)
Supply fan will operate at full speed or a limited speed not to exceed duct static pressure high limit.
Emergency Override
Emergency override provides the ability for a Building
Automation System to override control of the HVAC
equipment to pressurize, depressurize, purge, shutdown
ventilation to the space for life safety or smoke control
systems. Refer to summarizing the unit operation in
response to Emergency Override commands.
Ventilation Override Mode v/s. Emergency Override
Ventilation Override inputs/output directly connect to fire
smoke control station (FSCS) panel. UUKL 864 requires
that firefighters have the ability to manually override
automated smoke control equipment. Manual changes
from a FSCS panel will take precedence over Emergency
Override from the Building Automation System.
Table 44. Emergency override
Emergency Override Output Operation Heat Cool Mode Status
Shutdown Supply fan Off/0% Off
Outdoor air damper Closed
Relief fan / Relief damper Off/Closed
VAV Box Relay De-energized
Pressurize Supply fan On/100%
(a)
Fan Only
Outdoor air damper 100%
Relief fan / Relief damper
(b)
Off/Closed
Return fan/Relief damper
(b)
Off/Closed
VAV Box Relay Energized
Depressurize Supply fan Off/0% Fan Only
Outdoor air damper 0%
Relief fan / Relief damper
(b)
On/Open
Return fan/Relief damper
(b)
On/Open
VAV Box Relay De-energized
Purge Supply fan On/100% Fan Only
Outdoor air damper Open
Relief fan / Relief damper
(b)
On/Open
Return fan/Relief damper
(b)
On/Open
VAV Box Relay Energized
Unit Startup
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