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ACC-APG001A-EN
Space Temperature Control Sequence of Operation
Constant Volume and Multi-Speed Fan Configuration
Normal Operation
The Symbio 700 has a single-loop (space temperature only) control sequence. The sequence is
PI-based (proportional, integral) and strives to maintain space temperature within 1F of the active
cooling and heating setpoints.
• When Space Temperature Active > Space Temp Cooling Setpoint Status, the algorithm
calculates a need for cooling capacity to be energized.
• When Space Temperature Active < Space Temp Heating Setpoint Status, the algorithm
calculates a need for heating capacity to be energized.
• When Space Temp Heating Setpoint Status ≤ Space Temperature Active ≤ Space Temp
Cooling Setpoint Status:
– The algorithm calculates a reduction in need for any active cooling or heating capacity if
ON.
– If no cooling or heating capacity is active, cooling and heating capacity remains inactive.
Supply Fan Control
The supply fan is controlled “ON” 5 seconds before heating or cooling capacity is energized.
When heating or cooling capacity is de-energized, a supply fan off delay is applied based on
active capacity. For single-speed supply fan configured systems, the supply fan is controlled
“ON” during all cooling and heating sequences.
For multi-speed supply fan configured systems, the fan operates per the following:
• Low speed when the supply fan is ON without active capacity (unless ON due to an override
function)
• Low speed when the unit is operating at its minimum cooling stage
• High speed when the unit is operating at its maximum cooling stage or while any heating
stages are active.
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