Table 5. Calculating Actual VA Requirements
Item Sub VA Draw Per I/O (24 Vac)
Maximum Total VA Draw (24
Vac)
UC400 Board
UC400 (No I/O) 8 VA
5 x AI 0.2 VA per AI 1 VA
2 x UI 0.13 VA per UI 0.25 VA
2 x PI 0.13 VA per PI 0.25 VA
3 x BI 0.17 VA per BI 0.5 VA
2 x AO 1 VA Per AO 2 VA
3 x BO (Relay) 1 VA Per Relay (No Load) 3 VA
6 x BO (TRIAC) 0.34 VA Per TRIAC (No Load)
1 VA
Subtotal for UC400; 16 VA
24 Vdc Supply
200 mA
(a)
(a) See device connected to DC supply for current draw.
1 VA Per 25 mA DC 8 VA
Total for UC400; 24 VA
Binary Outputs (Relay and TRIAC)
BO1 to BO3 Refer to “Device Connections,” p. 11 Refer to “Device Connections,” p. 11
BO4 to BO9 0.5 A- 12 VA@ 24 Vac
12 VA Maximum
Below is an example calculation for a cooling-only box current requirements:
Description Draw
• UC400 no I/O
• Setpoint and Zone Temperature
•Flow
• Occupancy Input
• Binary for Air Damper (only one energized at a time, not including
ac
tuat
or draw)
•Total
•8 VA
•0.4 VA
• 0.13 VA
• 0.17 VA
• 0.34 VA
• 9.2 VA (Plus air damper draw)
With a Trane F Series Box: 13.2 VA Total
16 VAV-SVX07F-EN
Wiring Installation
• Replace the control box cover after field wiring to prevent any electromagnetic interference.
•Review Table 6 for factory-installed components and voltage amperage.
Table 6.
Style Volt Amps
F - Style Actuator 4 VA
Air Valve Actuator C through E Style 12 VA
Fan Power Fan Output 6 VA
Hot Water Proportional 4 VA
Hot Water 2 Position 6.5 VA
Electric Heater Magnetic Contactor 10 VA
Electric Heater Mercury Contactor 12 VA
Note: VariTrane cooling-only Series D and E models consume 20 VA (12 VA for the actuator and 8 VA for the board). The
heating output ratings remain the same.
Binary Load Valves
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