Delta Controls BACstat II Series User Manual

Error! No text of specified style in document. DNS-24, DNT-T103, & DNT-T221 Application Guide
Page 22 of 35
Document Edition 3.1
Setup Parameters
Setup Variable Function Notes
AV24 Binary Delay Transition Timer for Compressor
AV25 N/A
AV26 Binary Delay Transition Timer for Rev. Valve
AV27 N/A
AV28 PWM minimum value or Binary On Delay Depends on OP3 configuration
AV29 PWM maximum value or Time Proportioned
Heating Controller Limit
Depends on OP3 configuration
Sequence of Operation
If the Heating and Cooling controllers are both zero the control logic is in deadband and the compressor output is
turned O
FF.
If the Heating controller value exceeds 90% the control logic will switch to heating, and the reversing valve is
turned O
N if isn’t on already. After the transition timer has expired the compressor output will be turned ON.
The transition timer will then be reset (to the value set in the Setup variable AV24).
If the Cooling controller value exceeds 90% the control logic will switch to cooling, and the reversing valve is
turned O
FF if isn’t off already. After the transition timer has expired the compressor output will be turned ON.
The transition timer will then be reset.
The HPU algorithm may use a fan on Output 3, or have an auxiliary heating or cooling output of type Binary or
PWM or Timed Proportional.
When the fan type is ‘Intermittent’ the fan will start when the compressor starts. When the compressor stops the
fan will be turned off when the delay time has expired (Setpoint 28, Output 3 Binary Delay).
NOTE: The analog outputs on the DNT-T221 do not modulate, but provide a 0 or 10v signal
for the compressor and reversing valve, and require interface relays for switching purposes.
Switch to HEATING
 Turn Rev. Valve ON
 Wait Delay Time
Switch to COOLING
 Turn Rev. Valve OFF
 Wait Delay Time
Rev. Valve
is OFF
Rev. Valve
is ON
Heating > 90% Cooling > 90%
Turn Compressor ON
Heating &
Cooling = 0
HEATING COOLING
YY
NN
Turn Compressor OFF
DEADBAND
YYY
NN N
START
Turn Fan ONTurn Fan OFF

Delta Controls BACstat II Series Specifications

General

Brand	Delta Controls
Model	BACstat II Series
Category	Thermostat
Language	English