DNT-T103 & DNT-T221 Application Guide
Page 26 of 41
Document Edition 4.1
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 O
N
. 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 O
N
. 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
).
N
OTE
: The analog outputs on the DNT-T221 do not modulate, but provide a 0 or
5.
F
AN
C
OIL
U
NIT
(FCU)
– [Application (AV12) = 4]
10v
signal for the compressor and reversing valve, and require interface relays for
switching purposes.
Function: Control of a simple Fan Coil Unit with fan.
DNT-T103 I/O (Outputs 1 to 3 are Triacs)
Input AI1
Input AI2 Input AI3 Remote AV5
Output 1
Output 2
Output 3
Room Temp.
N/A
Optional OAT
Heating 1
Heating 2
Fan
Room Temp.
N/A
Optional OAT
Heating 1
Cooling 1
Fan
Room Temp.
N/A
Optional OAT
Heating 1
MUX
Fan
Room Temp.
N/A
Optional OAT
Cooling 1
Heating 1
Fan
Room Temp.
N/A
Optional OAT
Cooling 1
Cooling 2
Fan
Room Temp.
N/A
Optional OAT
Cooling 1
MUX
Fan
Room Temp.
N/A
Optional OAT
Tri-State
Heating (Open)
Tri-State
Heating (Close)
Fan
Room Temp.
N/A
Optional OAT
Tri-State
Cooling (Open)
Tri-State
Cooling (Close)
Fan
DNT-T221 I/O (Outputs 1 & 2 are Analog, and Output 3 is a Triac)
Input AI1
Input AI2 Input AI3 Remote AV5
Output 1
Output 2
Output 3
Room Temp.
N/A
Optional OAT
Heating 1
Heating 2
Fan
Room Temp.
N/A
Optional OAT
Heating 1
Cooling 1
Fan
Room Temp.
N/A
Optional OAT
Heating 1
MUX
Fan
Room Temp.
N/A
Optional OAT
Cooling 1
Heating 1
Fan
Room Temp.
N/A
Optional OAT
Cooling 1
Cooling 2
Fan
Room Temp.
N/A
Optional OAT
Cooling 1
MUX
Fan
Setup Parameters
Setup Variable
Function
Notes
AV24
PWM minimum value or Binary On Delay or
Actuator Runtime (Tri-State Valves)
Depends on OP1 configuration
AV25
PWM maximum value
Depends on OP1 configuration
AV26
PWM minimum value or Binary On Delay
Depends on OP2 configuration
