3.22 Main Menu - Application Functions 2 - Group 24
3.22.1 24-0* Fire Mode
NOTE!
Please note the adjustable frequency drive is only one component of the VLT HVAC Drive system. Correct function of fire mode depends
on the correct design and selection of system components. Ventilation systems working in life safety applications have to be approved
by the local fire authorities.
Non-interruption of the adjustable frequency drive due to fire mode operation may cause
overpressure and result in damage to VLT HVAC Drive system and components, including dampers and air ducts. The
adjustable frequency drive itself may be damaged and it may cause damage or fire. Danfoss accepts no responsibility
for errors, malfunctions, personal injury or any damage to the adjustable frequency drive itself or components herein,
VLT HVAC Drive systems and components herein or other property when the adjustable frequency drive has been
programmed for fire mode. In no event shall Danfoss be liable to the end user or any other party for any direct or
indirect, special or consequential damage or loss suffered by such party, which has occurred due to the adjustable
frequency drive being programmed and operated in fire mode.
Background
Fire mode is for use in critical situations, where it is imperative for the motor to keep running, regardless of the adjustable frequency drive’s normal
protective functions. These could be ventilation fans in tunnels or stairwells for instance, where continued operation of the fan facilitates safe evacuation
of personnel in the event of a fire. Some selections of the fire mode function cause alarms and trip conditions to be disregarded, enabling the motor to
run without interruption.
Activation
Fire mode is activated only via digital input terminals. See par. 5-1* Digital Inputs.
Messages in display
When fire mode is activated, the display will show a status message “Fire Mode” and a warning “Fire Mode”.
Once fire mode is again deactivated, the status messages will disappear and the warning will be replaced by the warning “Fire M Was Active”. This
message can only be reset by power-cycling the adjustable frequency drive supply. If, while the adjustable frequency drive is active in fire mode, a
warranty-affecting alarm (see par.24-09
) should occur, the display will show the warning “Fire M Limits Exceeded”.
Digital and relay outputs can be configured for the status messages “Fire Mode Active” and the warning “Fire M Was Active”. See par. 5-3* and par. 5-4*.
“Fire M was Active” messages can also be accessed in the warning word via serial communication. (See relevant documentation).
The status messages “Fire Mode” can be accessed via the extended status word.
Message
Type
LCP
Digital Out/Relay
Warning Word 2
Ext. Status Word 2
Fire Mode
Status
+
+
+ (bit 25)
Fire Mode
Warning
+
Fire M was Active
Warning
+
+
+ (bit 3)
Fire M Limits Exceeded
Warning
+
+
Log
An overview of events related to fire mode can be viewed in the fire mode log, par. 18-1*, or via the Alarm Log button on the LCP.
The log will include up to 10 of the latest events. Warranty-affecting alarms will have a higher priority as the two other types of events.
The log cannot be reset!
Following events are logged:
*Warranty affecting alarms (see par.24-09
, Fire Mode Alarm Handling)
*Fire Mode activated
3 Parameter Description
VLT
®
HVAC Drive Programming Guide
3-228
MG.11.C6.22 - VLT
®
is a registered Danfoss trademark
3