Trane Climate Changer TCFS Nstallation, Operation, And Maintenance page 58

Start-Up
Figure 66. Traq damper terminal connections
VCM (Transducer) Calibration.
zero function that recalibrates the transducer once every
minute. When troubleshooting, allow for the recalibration
time before making any measurements.
Input Power.
The only input the VCM needs is the 24 Vac
power connected to the J2 plug (green and black wires).
Output Velocity Signal.
signal from the VCM represents air velocity. This voltage
can be converted to represent airflow (cfm or L/s) using
this formula and Table 4.
Table 5. Back or top inlet Traq dampers - air-mixing and economizer section - VCM voltage versus airflow at sea level
Traq Damper
Part Number Size (inches)
DMP01123 13
DMP01124 16
DMP01663 20
DMP01125 24
DMP01126 28
58
The VCM has an auto-
The 2 to 10 Vdc linear output
Quantity Total Area (ft
1
1
1
1
1
Airflow = k (cfm @ 10V)
or
Airflow = k (L/s @ 10V)
For example, if the VCM on a size 30 air handler at sea
level (k=1) has a 10-volt signal, it would represent
24,492 cfm (11,559 L/s) through the Traq damper. If
the voltage were 6 volts, airflow through the Traq
damper would be 12,246 cfm (5779 L/s).
Table 4. Altitude adjustment factors
Elevation (feet)
1000
2000
3000
4000
5000
6000
7000
8000
9000
10,000
In Table 5, the cfm at 10Vdc is a calculated value based on
area and peak velocity. In certain 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. Calculations are based on VCM voltage versus
airflow at sea level.
Peak Velocity
2
) (fpm)
0.9213 2500
1.3956 2650
2.1806 2650
3.1400 2700
4.2739 2700
( volts 2 )
–
------------------------------
8
volts 2
( )
–
------------------------------
8
Sea level = 1.0
k
0.982
0.964
0.949
0.930
0.914
0.897
0.876
0.860
0.846
0.825
CFM @ 10VDC
Peak Velocity L/S @ 10VDC
2303
3698
5779
8478
11540
CLCH-SVX010A-EN
1087
1745
2727
4001
5446