Trane Voyager Commercial, Installation, Operation And Maintenance Manual

Page: 62 / 156

62 RT-SVX34R-EN
Figure 47. Transducer voltage output vs. pressure
input for building pressure
Power Exhaust Control (Tracking)
The power exhaust dampers proportionally track or
follow the fresh air (economizer) damper position. The
offset between the fresh air and the exhaust damper(s)
is adjustable, see figures beginning with
, p. 83 . Refer
to Power Exhaust Fan Performance” tables beginning
with
Table 53, p. 83 .
Lead/Lag Control
Lead/Lag is a selectable input located on the RTRM. On
2 & 3 stage standard efficiency units, the RTRM is
configured from the factory with the Lead/Lag control
disabled. To activate the Lead/Lag function, simply
remove the jumper connection J3-8 at the RTRM Lead/
Lag input. When it is activated, each time the
designated lead compressor(s) is shut off due to the
load being satisfied, the lead compressor or
refrigeration circuit switches. On the 5 stage high
efficiency units, the RTRM is configured from the
factory with the Lead/Lag control enabled. With it
active, each time the designated lead compressor is
shut off due to the load being satisfied, the controls will
switch to the next staging sequence. When the RTRM is
powered up, i.e. after a power failure, the control will
default to the number one compressor.
Table 36. Capacity steps with lead/lag enabled - std
Efficiency
Unit Size
Step 1 Step 2 Step 3
TC*330
LEAD 48% 100%
LAG 52% 100%
TC*360
LEAD 50% 100%
LAG 50% 100%
TC*420
LEAD 47% 100%
LAG 53% 100%
TC*480 VAV
only
LEAD 40% 60%
100%
LAG 60% 100%
Table 36. Capacity steps with lead/lag enabled - std
Efficiency (continued)
Unit Size
Step 1 Step 2 Step 3
TC*600 VAV
only
LEAD 32% 68%
100%
LAG 68% 100%
Table 37. Capacity staging sequence - high Efficiency
& 40–50 tons std eff CV
Steps
Unit Size
Sequence
1 2 3 4 5
TC*330
1 25 37 63 75 100
2 37 63 75 100
3 37 63 75 100
TC*360
1 24 38 62 76 100
2 38 62 76 100
3 38 62 76 100
TC*420
1 22 39 61 78 100
2 39 61 78 100
3 39 61 78 100
TC*480
1 23 39 61 77 100
2 39 61 77 100
3 39 61 77 100
TC*600
1 25 38 62 75 100
2 38 62 75 100
3 38 62 75 100
Coil Frost Protection
The Frostat ™ control monitors the suction line
temperature to prevent the evaporator from freezing
due to low operating temperatures whenever there is a
demand for cooling. When a closed circuit has
occurred for 5 seconds minimum, the RTRM turns off
all of the cooling outputs. The Supply Fan will be held
“
“O On n” ” until the Frostat has been open for 5 continuous
seconds or for 60 seconds after the last compressor
was shut “
“O Offff” ”, whichever is the longest. The
compressor shutdown is communicated to Tracer, if
applicable. There is no local diagnostic for this
condition.
Modulating Hot Gas Reheat Frost
Protection
Two control schemes will be active on units configured
for Modulating Hot Gas Reheat. The first employs the
use of the Frostat function. The second scheme takes
precedence over Frostat. Operation will be as described
below.
The second scheme is in control during active hot gas
reheat or cooling and includes the use of an Entering
S Stta arrttu up p