Trane Climate Changer M Series Installation Operation & Maintenance page 78

Startup
VCM (Transducer) Calibration.
transducer once every minute. When troubleshooting, allow for the recalibration time before
making any measurements.
Input Power.
and 1TB1–6.
Output Velocity Signal.
velocity. This voltage can be converted to represent airflow (cfm or L/s) using the formula below,
Table 17
In
situations, it can be advantageous to raise the velocity of air through the remaining Traq dampers
by closing off one or more dampers in the unit. The cfm at 10Vdc can be recalculated based on the
proportion of remaining Traq dampers or by multiplying the remaining area of dampers by peak
velocity.
Table 17. Altitude adjustment factors
Sea level = 1.0
Elevation (feet)
1000
2000
3000
4000
5000
6000
7000
8000
9000
10,000
Table 18. Back or Top Inlet Traq Dampers - Air-Mixing and Economizer Section - VCM voltage versus airflow at sea level
Unit Part
Size Number
03
06
DMP01123
08
10
12
14 DMP01124
17
21
DMP01125
25
30 DMP01663
35
DMP01125
40
50
57
66
DMP01126
80
100
120
78
The only input the VCM needs is the 24 Vac power connected to terminals 1TB1–5
and Table 18.
Table 18 the cfm at 10Vdc is a calculated value based on area and peak velocity. In certain
k
0.982
0.964
0.949
0.930
0.914
0.897
0.876
0.860
0.846
0.825
Traq Damper
Size (inches) Quantity
1
13 2
3
16 3
24 2
20 3
24 3
3
4
28
5
6
The VCM has an auto-zero function that recalibrates the
The 2 to 10 Vdc linear output signal from the VCM represents air
Airflow = k (cfm @ 10V)
or
Airflow = k (L/s @ 10V)
For example, if the VCM on a size 30 M-Series air handler at sea level
(k=1) has a 10-volt signal, it would represent 18,376 cfm (8672 L/
s) through the Traq damper. If the voltage were 6 volts, airflow
through the Traq damper would be 9,188 cfm (3,930 L/s).
Total Area Peak Velocity
2
ft
0.9213
1.8426
2.7639
4.1867
6.2800
6.5417
9.4200
12.8217
17.0956
21.3694
25.6433
( volts 2 )
–
------------------------------
8
( volts 2 )
–
------------------------------
8
CFM@10VDC
(fpm) Peak Velocity
2303
2500 4606
6910
2650 11095
2700 16956
2650 17335
2700 25434
34619
46158
2700
57698
69237
L/s@10VDC
1087
2174
3261
5236
8002
8181
12004
16338
21784
27230
32676
CLCH-SVX03C-EN