RT-SVP011E-EN 53
TD7 Display
Entering a Supply Fan VFD Bypass Event
• At all times when the unit is not in an active Supply Fan VFD Bypass Mode, the Supply Fan
Bypass Relay will be commanded OFF (de-energized).
• The user will not be allowed to place the unit into an active Supply Fan VFD Bypass Mo
de at
the TD7 Display until all of the following has occurred:
• Th
e user has requested Unit Stop Mode at the display.
• All components have been commanded OFF or CLOSED.
• The supply fan proving logic indicates a no-flow condit
ion has existed for 40 continuous
seconds.
• When the user places the unit into an active Supply Fan VFD Bypass Mode at the TD7
Display,
all of the following will be enforced:
• For Multi Zone VAV units the VAV Box Relay will be commanded ON (energized) to indic
ate
full airflow mode to the system, and the VAV Box Stroke Time will count down (active
Ventilation Override Modes that have VAV Box Relay set to OFF have higher priority and the
relay will be commanded OFF).
• Alth
ough the user can request Unit Auto Mode from
the display it will be pending, and the
unit will keep all components OFF or CLOSED until the VAV Box Stroke Time has timed out.
• On
non-Multi Zone VAV units, once the unit has entered active Supply Fan Bypass Mode the
supply fan(s) wi
ll be allowed to run once the user has requested Unit Auto Mode at the
display.
• When the unit enters active supply fan operation, and supply fan proving is satisfied, the unit
will run in
constant volume supply fan mode.
• During active bypass mode the unit’
s supply fan log
ic will turn the Supply Fan Bypass Relay
On and Off to run or stop the fan(s).
Exiting a Supply Fan VFD Bypass Event
• The user will not be allowed to remove the unit from an active Supply Fan VFD Bypass Mode
at the TD7 Display until all of the following has occurred:
• The user has requested Unit Stop Mode at the display.
• All components have been commanded OFF or CLOSED.
• The supply fan proving logic indicates a no-flow con
dition has existed for 40 continuous
seconds.
• When the user removes the unit from active Supply Fan VFD Bypass Mode at t
he display, all
of the following will be enforced:
• T
he Supply Fan Bypass Relay will remain OFF.
• For Multi Zone – VAV units the VAV Box Relay will be commanded OFF (de-energized) to
indicate normal airflow mode to the system, and the VAV Box Stroke Time will count down.
• Once the above conditions have been satisfied the user w
ill be allowed to request Unit Auto
Mode at the display.
• At all times when the unit is not in an active Supply Fa
n VFD Bypass Mode, the Supply Fan
Bypass Relay will be commanded OFF (de-energized).
Ventilation Override (if configured)
Allows modification and locking of Ventilation Override Modes.
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