
VAV-SVX01C-EN
51
Sequence of Operations
Recalibrate (Reset)
The recalibrate function can be enabled.
Series Fan-Powered Units
Occupied Units
Air valve control for series fan-powered units is the same as both single duct and parallel fan-
powered units. During the occupied mode of operation, the series fan is continuously energized.
Heat stages are energized on the following schedule:
Override Conditions (Series Fan)
The UCM occupied controls can be overridden by the following override commands:
Unoccupied
If the control mode is edited to unoccupied, the unoccupied cooling and heating temperature set
points are used for temperature control. The series fan and heat outputs will be activated as
necessary to maintain the current unoccupied set points. The fan control point is not utilized on
series units. On electric heating and hot water heating units, the fan and heat are energized at the
unoccupied heating set point. The minimum cooling flow set point is reset to zero unless
minimums are being enforced by a group override. A series fan will be energized anytime the air
valve’s position is greater than 0%.
Heating
If the control action is edited to HEAT, the UCM controls the air valve as a heating source rather than
cooling. The unit fan remains operational. Unit heat on an electric heat unit is locked out, but
remains active on hot water units.
Flow Control Override
Flow control may be overridden by any of the following commands:
•
Drive Air Valve Fully Open. The air valve will be driven fully open. Fan operation is unaffected,
but heat outputs are locked out.
•
Drive Air Valve Fully Closed. The air valve is driven fully closed. The fan and heat outputs are
locked out.
•
Drive Air Valve to Minimum Flow. The air valve is driven to the minimum airflow set point. The
fan and heat outputs remain operational.
•
Drive Air Valve to Maximum Flow. The air valve is driven to maximum airflow set point. The
fan and heat outputs remain operational.
Heat Control Override
Heat control can be disabled locking out heat outputs.
Fan Control Override
Fan control override does not affect fan operation on series fan-powered units.
Table 12. Heat stages
Stage
ON Switch point
OFF Switch point
1
At the heating set point
0.5°F above the heating set point
2
1°F below the heat set point
0.5°F below the heat set point
Содержание VAV-UCM 4.2
Страница 1: ...May 2010 VAV SVX01C EN Installation Operation Maintenance VAV UCM 4 2...
Страница 81: ...VAV SVX01C EN 81 Troubleshooting Figure 46 Single duct with single phase voltage electric heat...
Страница 82: ...82 VAV SVX01C EN Troubleshooting Figure 47 Single duct with three phase voltage electric heat...
Страница 83: ...VAV SVX01C EN 83 Troubleshooting Figure 48 SCR PSC fan powered with single phase voltage electric heat...
Страница 84: ...84 VAV SVX01C EN Troubleshooting Figure 49 SCR PSC fan powered with three phase voltage electric heat...
Страница 85: ...VAV SVX01C EN 85 Troubleshooting Figure 50 ECM fan powered with single phase voltage electric heat...
Страница 86: ...86 VAV SVX01C EN Troubleshooting Figure 51 ECM fan powered with three phase voltage electric heat...