Trane ACONT900AC43UA Service Manual page 162

Gas Valves
Step 9
Once the low heat gas pressure is adjusted, use the
Installer Test to select 100% (high) heat. Using
Installer Test #3 in a dual fuel application, select 4
on the right hand side of the screen using the UP
arrow for 100% (high) heat (Figure 24).
Figure 24
Step 10
Using Installer Test #4 in a furnace only application,
select 2 on the right hand side of the screen using the
UP arrow for 100% (high) heat.
Step 11
Let the furnace go through the 100% (high) heat
inducer learning routine and have its temperature rise
stabilize. The temperature rise and learning routine
will take approximately three minutes. Read the 100%
(high) heat manifold gas pressure (Figure 25).
NOTE: The adjustment cover on the 100% (high)
heat pressure adjustment screw must be in place
during manifold gas pressure readings.
GF - D 10
Figure 25
Step 12
If needed, remove the 100% (high) heat pressure
adjustment cover and adjust the gas valve's 100%
(high) heat pressure adjustment screw to obtain the
correct pressure (Figure 26). Use Manifold Pressure
Settings Table 4 for the correct 100% (high) heat
pressure setting in inches of Water Column pressure.
100% (HIGH)
COUNTERCLOCKWISE TO DECREASE PRESSURE
OR CLOCKWISE TO INCREASE PRESSURE.
Figure 26
Step 13
Replace and tighten the adjustment cover for the 100%
(high) heat adjustment screw and then read the
manifold pressure again. This procedure may need to
be repeated until the manifold gas pressure is 3.5
inches of Water Column.
HEAT ADJUSTMENT: