Application

Application Notes
Dual Duct Sequence Configurations
8
Siemens Industry, Inc.
Application Note
A6V11692042
Smart Infrastructure – Building Products
2019-04-01
Dual Duct Sequence Configurations
Note
Default settings assign Duct 1 as cold duct and Duct 2 as hot duct, but these
assignments are configurable / reversible if desired or required. The following
examples use the default assignments for cold duct and hot duct (use case 4 is
special case, see below).
Use case 1: VAV DD - Ventilation source in one duct
• 1a - Ventilation in cold duct (Duct 1)
• 1b - Ventilation in hot duct (Duct 2)
Use case 2: VAV DD - Ventilation in both ducts, with mixing control
• 2a - Cold duct ventilation in deadband
• 2b - Hot duct ventilation in deadband
• 2c - Last duct ventilation in deadband
Use case 3: VAV DD - Ventilation in both ducts, snap acting control
• 3a - Cold duct ventilation in deadband
• 3b - Hot duct ventilation in deadband
• 3c - Last duct ventilation in deadband
Use case 4: VAV DD - Dedicated duct for ventilation from DOAS (dedicated outside
air system)
Use case 5: Constant volume DD option - Ventilation in both ducts, with mixing
control
• 5a - Cold duct ventilation in deadband
• 5b - Hot duct ventilation in deadband
Main objects / parameters for dual duct use case configurations:
Name
Description
Available settings
VavSuChovrCnd1
(1VAV CHGVR)
Changeover object for Duct 1
1:Neither
2:Heating
3:Cooling (default)
4:Neutral
VavSuChovrCnd2
(2VAV CHGVR)
Changeover object for Duct 2
1:Neither
2:Heating (default)
3:Cooling
4:Neutral
VntDuctSprt
Parameter that defines which duct(s) provide
ventilation air flow
1:No ventilation
2:Duct 1
3:Duct 2
4:Both ducts
CtlStrgy
Parameter that defines whether mixing control is
supported by the dual duct configuration
1:Snap acting control
2:Mixing control
VntSprtDdband
Parameter that defines how ventilation is provided
during temperature deadband
1:Duct 1
2:Duct 2
3:Last duct