Distech Controls ECB-VAVS - Heat Control and Output Wiring

15ECB-VAVS Preloaded Applications
Heat Control and Output Wiring
Heat Control
Depending on the controller model, up to three heating sources can be controlled. Configuration of
these sources is done by the following variables:
£ Heat1Type (MV21)
£ Heat2Type (MV22)
These variables allow the user to select the type of control signal used to drive the heating source.
These variables must be configured in order (i.e. Heat1Type must be used before Heat2Type can be
configured, and so on).
Each heat type has a normally open or normally closed configuration option, represented by the fol-
lowing variables:
£ Heat1NormOpen (BV20)
£ Heat2NormOpen (BV21)
Other relevant variables are described in the table below.
Variable Description
DuctHeatStgs (MV29)
This variable determines the number of duct heaters which are installed. Duct heaters are
always wired starting from Heat1Type. If no duct heaters or only perimeter heat is
required, set this variable to “None”. All heat types configured greater than DuctHeatStgs
are considered perimeter heaters.
MaxOatDuctHeat (AV48) Outside air temperature limit to disable the duct heater(s).
MaxOatPerimHeat (AV49) Outside air temperature limit to disable the perimeter heater(s).
HeatPriority (MV13)
Determines which heating source is activated first. Options are duct heater, perimeter
heat or simultaneous.
HotWaterReheat (BV18)
Determines if hot water reheat is used. When in use, the MinFlowHeatSP safeguard is
ignored.
Shedding (AV11)
Load shedding Option. A value of zero percent disables this feature. Shedding between 0
and 100 percent attenuates the total heat demand of the system.
Shedding
Shedding is based on the following variable:
Variable Description
Shedding (AV11)
Load shedding option. 0% = no shedding; 100% = full shedding
Heating output is rescaled based on the percentage of shedding required.
Example:
Heating demand = 75%
Shedding = 20%
Max heating = 100% - 20% (shedding) = 80%
Output = 75% (heating demand) x 80% (max heating) = 60% (Scaled output based on required shed-
ding)
Sequence of Operation