23
DAMPER TRANSFORMER
TRANSFORMER/FUSE SIZING
NUMBER
OF
DAMPERS
1
40 VA
1 AMP
40 VA
1 AMP
2
40 VA
2 AMP
40 VA
1 AMP
3
40 VA
2 AMP
40 VA
1 AMP
4
40 VA
3 AMP
40 VA
2 AMP
5
48 VA
3 AMP
40 VA
2 AMP
6
60 VA
4 AMP
40 VA
2 AMP
7
72 VA
5 AMP
40 VA
3 AMP
8
84 VA
5 AMP
42 VA
3 AMP
9
96 VA
6 AMP
48 VA
3 AMP
10
108 VA
6 AMP
54 VA
3 AMP
11
120 VA
7 AMP
60 VA
4 AMP
12
132 VA
7 AMP
66 VA
4 AMP
XFMR PWR
FUSE SIZE
Notice: All wiring must meet state and local codes.
STARTUP TEST, GAS/ELECTRIC DT4U
DAMPER TRANSFORMER SIZING AND STARTUP
The 24V transformer connected to TR1 and TR2 of the Digitract 4 System Controller powers the zone dampers. The power
rating of the transformer must be sufficient to power the number of dampers used. Also, a properly rated in line fuse must be
used on the secondary of the transformer. To determine the power rating of the transformer and the amperage rating of the
fuse, use the table below. If using a combination of spring open and power open dampers, size as if all dampers are spring
open.
Note: The System Controller and thermostats are powered by the HVAC unit transformer via terminals R and C.
TR SERIES
(SPRING OPEN) DAMPERS
MED. PRESSURE/HEAVY DUTY
(POWER OPEN) DAMPERS
XFMR PWR
FUSE SIZE
b. At thermostat:
1. Set power switch to ON, if applicable.
2. Set to Heat mode.
3. Set fan switch to AUTO mode
4. Set heat setpoint 4° above room temperature.
c. Verify that air is now coming out of register.
10. At previous zone, turn off thermostat, and verify there is no
airflo
w. Verify that DPR 2 is OFF and DPR 1, 3 and 4 are ON.
11. Repeat steps 9 and 10 for remaining zones.
12. Turn off all thermostats except zone 1.
13. At zone 1 thermostat:
a. Set power to ON, if applicable.
b. Set to Cool mode.
c. Set fan switch to AUTO mode.
d. Set cool setpoint 4° below room temperature.
14. At System Controller:
a. Verify Y1, G and PWR LEDs are on. If not, cycle System
Controller power switch OFF and ON and recheck.
b. Verify that DPR 1 LED is OFF and DPR 2 through 4 are ON.
15. At HVAC unit, verify air conditioner and blower are running.
16. Verify that air is coming out of registers.
17. After 8 minutes, check LAT. If LAT is above LO cutout plus
12°, verify that Y2 energizes. If LAT is less than LO cutout plus
12°, remove LAT from supply plenum and verify Y2 operation.
1. If there is no heating system, go to step 12
2. At System Controller:
a. Turn power switch to ON. Verify power LED is illuminated.
3. Turn off all thermostats except thermostat 1.
4. At zone 1 thermostat:
a. Set power switch to ON, if applicable.
b. Set to Heat mode.
c. Set fan switch to AUTO mode.
d. Set heat setpoint 4° above room temperature.
5. At System Controller:
a. Verify W1 and PWR LEDs are ON. If not, cycle System Controller
power switch OFF and then ON and recheck.
b. If fan jumper is across middle and top pin, verify that G is ener-
gized for fan operation in Heat mode.
c. Verify that DPR 1 LED is OFF and DPR 2 through DPR 4 are ON.
6. At furnace, verify that furnace is on and blower fan is running. If
the G LED on System Controller is not on, the blower fan is
controlled by the furnace and there will be a delay before it turns
on.
7. At zone 1, verify that air is coming out of register. verify that W2
LED energizes and if 2nd stage heat is available, 2nd stage
starts.
8. After 4 minutes of W1 run time, check LAT. If LAT is less that HI li-
mit minus 25°, then W2 will energize. If LAT is greater than HI limit
minus 25°, remove LAT from supply plenum and verify that W2 LED
energizes and, if 2nd stage heat is available, 2nd stage starts.
9. At next zone:
a. Verify that no air is coming out of register.
