Programming Guide

72 VAV-SVP01A-EN
Sequence of Operations
Space Temperature Control: Fan-Powered Units
VAV VV550/VV551 Controllers provide three fan options when in space temperature control mode:
• One-speed ON/OFF series fan;
• One-speed ON/OFF parallel fan;
• Fan Off Delay
Table 11. Local heat only with no fan present
Configuration Method of control
Local Remote Stage 1 Stage 2 Stage 3
PWM electric
(1 to 3 stages)
Not applicable Local PI capacity loop
Each stage represents an equal percentage of total capacity PWM Output (one stage = 100%; two stages
= 50% each; three stages = 33.33% each). Total capacity is limited by communicated auxiliary heat enable.
On/Off electric
(1 to 3 stages)
Not applicable Local thermostatic
On: Zt < HSP
Off: Zt
≥ HSP + 0.5°F (0.28°C)
Local thermostatic
On: Zt < HSP - 1°F (0.56°C)
Off: Zt
≥ HSP - 0.5°F (0.28°C)
Local thermostatic
On: Zt < HSP - 2°F
Off: Zt
≥ HSP - 1.5°F
Each stage represents an equal percentage of total capacity. Total capacity is limited by communicated
auxiliary heat enable.
On/Off hot water
(1 stage)
Not applicable Local thermostatic
On: Zt < HSP
Off: Zt
≥ HSP + 0.5°F (0.28°C)
Not applicable Not applicable
Total capacity is limited by
communicated auxiliary heat
enable.
Not applicable Not applicable
Modulating hot
water
Not applicable Local PI capacity loop
Modulating valve capacity = Total capacity
Valve drive Incrementally open/closed
Total capacity limited by communicated auxiliary heat enable
Not applicable
Note: Abbreviations: Zt = Zone temperature; HSP = Heating setpoint
Table 12. Local heat only with parallel/series fans present
Configuration Method of control
Local Remote Stage 1 Stage 2 Stage 3
Fan Not applicable Parallel/Series Fans Not applicable Not applicable
Fan +
PWM electric
(1 to 2 stages)
Not applicable Parallel/Series Fans Local PI capacity loop
Each stage represents an equal percent of total capacity (1-stage = 100%, 2
stages = 50% each) PWM output
Total capacity is limited by communicated auxiliary heat enable.
Fan +
On/Off electric
(1 to 2 stages)
Not applicable Parallel/Series Fans Local thermostatic
On: Zt < HSP - 1°F (0.56°C)
Off: Zt
≥ HSP - 0.5°F (0.28°C)
Local thermostatic
On: Zt < HSP - 2°F (1.11°C)
Off: Zt ≥ HSP - 1.5°F (0.83°C)
Each stage represents an equal percentage of total capacity. Total capacity is
limited by communicated auxiliary heat enable.
Fan +
On/Off hot water
(1 to 2 stages)
Not applicable Parallel/Series Fans Local thermostatic
On: Zt < HSP - 1°F (0.56°C)
Off: Zt
≥ HSP - 0.5°F (0.28°C)
Not applicable
Total capacity is limited by
communicated auxiliary heat enable
Not applicable
Fan +
Modulating hot
water
Not applicable Parallel/Series Fans
Local PI capacity loop
Modulating valve capacity = Total capacity
Valve drive incrementally open/closed
Total capacity limited by communicated auxiliary heat enable
Note: Abbreviations: Zt = Zone temperature; HSP = Heating setpoint