Operating instructions
3.22 Main Menu - Application
Functions 2 - Group 24
3.22.1 24-0* Fire Mode
Please note the frequency converter 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 frequency converter due to Fire Mode operation
could cause over pressure and result in damage to VLT
HVAC Drive system and components, hereunder dampers
and air ducts. The frequency converter itself could be
damaged and it may cause damage or fire. Danfoss
accepts no responsibility for errors, malfunctions personal
injury or any damage to the frequency converter itself or
components herein, VLT HVAC Drive systems and
components herein or other property when the frequency
converter 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
frequency converter 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 frequency
converter’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 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
parameter group 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 the 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 frequency converter supply. If, whilst the
frequency converter is active in Fire Mode, a warranty-affect-
ing alarm (see par. 24-09 Fire Mode Alarm Handling) should
occur, 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 parameter group5-3* and parameter group 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 Messages in display 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, parameter group 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 Alarm Handling)
*Fire Mode activated
*Fire Mode deactivated
All other alarms occurring while Fire Mode activated will be
logged as usual.
Parameter Description
VLT
®
HVAC Drive Programming Guide
MG.11.CA.02 - VLT
®
is a registered Danfoss trademark 161
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