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Monitor Module Operation
F.2.2 HVAC OVRRIDE
The HVAC OVRRIDE type code can be assigned to any addressable monitor module for the
purpose of overriding or preventing the HVAC SHUTDN control modules from activating. The
HVAC OVRRIDE monitor module acts globally throughout the FACP system and therefore is not
programmed to a particular software zone. To program this feature in the FACP:
•
Program the HVAC OVRRIDE type code to the monitor module which will be used to
override the HVAC SHUTDN control module and prevent the fans from turning off (refer to
Type Monitor under the section titled "Edit Module Screen for Monitor Module" on page 79).
The HVAC OVRRIDE monitor module does not latch when activated. Activating a switch
connected to the monitor module will override all HVAC SHUTDN control relay modules in the
system, preventing the HVAC SHUTDN modules from activating and causing the FACP LCD to
display an active HVAC OVRRIDE module and turn on the Supervisory LED. Releasing the
switch will allow the HVAC SHUTDN control relay modules to activate with subsequent alarms,
turning off the fans.
As an example, pressing the HVAC OVRRIDE switch with no alarms in the system will prevent the
fans from being turned off when an alarm does occur. As long as the switch is activated, the fans
will not shutdown for any alarms. If the system is still in alarm when the switch is released, the
fans will not shutdown unless another alarm occurs after the switch is released.
Important! If an alarm exists in the system and HVAC Shutdown has already occurred, HVAC
OVRRIDE will have no effect on the HVAC SHUTDN control relay modules. HVAC OVRRIDE
will prevent HVAC Shutdown from occurring only if it is initiated prior to an alarm condition.
NOTE: Activation of the HVAC OVRRIDE module causes a supervisory event that will be
communicated to the Central Station if enabled.
MS-9600LS Series Manual — P/N 52646:B2 2/12/2010
HVAC Control
199
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