BAS-SVX080B-EN
49
Figure 42.
Supply fan bypass mode enable button
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 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 condition 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
indicate 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).
–
Although 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) will 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 logic 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.
Содержание TCONT 800 Series
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