Application

Application Notes
Sequence of Operation – Summary
27
Siemens Industry, Inc.
Application Note
A6V11692042
Smart Infrastructure – Building Products
2019-04-01
⚫ ECO HTG STPT – Heating setpoint for economy (SpHEco)
⚫ PROT CLGSTPT – Cooling setpoint for protection (SpCPrt)
⚫ PROT HTG SP – Heating setpoint for protection (SpHPrt)
⚫ H.C STATE – Heating/cooling state (HCSta)
Supply airflow setpoints
Min and max supply airflow heating and cooling setpoints, separately configurable:
⚫ HTG FLOW MIN – Supply air VAV minimum air volume flow for heating
(VavSuAirFlMinH)
⚫ HTG FLOW MAX – Supply air VAV maximum air volume flow for heating
(VavSuAirFlMaxH)
⚫ CLG FLOW MIN – Supply air VAV minimum air volume flow for cooling
(VavSuAirFlMinC)
⚫ CLG FLOW MAX – Supply air VAV maximum air volume flow for cooling
(VavSuAirFlMaxC)
Min and max supply airflow ventilation setpoints:
⚫ VENT FLO MIN – Supply air VAV minimum air volume flow for ventilation
(VavSuAflMinVnt)
⚫ VENT FLO MAX – Supply air VAV maximum air volume flow for ventilation
(VavSuAflMaxVnt)
Additional ventilation parameters, separately configurable per occupancy mode:
⚫ Room minimum ventilation flow setpoints
⚫ Room DCV indoor air quality ppm setpoints
Dual Duct VAV Box Sequence with Modulating Hot Water Heat
a)
Cooling – When the room temperature [RM TEMP EVAL] rises above the effective cooling
setpoint [CLG STPT EFF], the cold duct supply damper modulates from the cooling or vent
flow minimum (whichever is larger) to the cooling flow max to satisfy CLG STPT EFF.
b)
Heating – When the room temperature is below the effective heating setpoint [HTG STPT
EFF], the hot duct supply damper and hot water coil are controlled as follows:
The hot water heating coil is modulated to maintain supply air temperature setpoint as reset
by room temperature demand. The terminal box maintains the larger of minimum ventilation
airflow or heating airflow. If the effective heating setpoint cannot be maintained using the
minimum flow level, the supply damper will modulate to heating flow max as required to
satisfy HTG STPT EFF.
c)
Ventilation in deadband (configurable) – When the room temperature is between the effective
heating and cooling setpoints, the assigned ventilation supply damper is positioned at the
ventilation minimum flow setting.
d)
Warm-up cycle (via central command) – The assigned heating duct supply damper is
positioned at heating flow max and the heat coil is modulated to satisfy the effective heating
setpoint.
e)
Cool down cycle (via central command) – The assigned cooling duct supply damper is
positioned at cooling flow max and the heating coil(s) are closed / turned off to satisfy the
effective cooling setpoint.