Trane ACONT900AC43UA Service Manual page 167

• UNIT TEST and NO (NO)
Use the or arrow button to change the NO to a
YES and then press ENTER.
• ARE YOU SURE and NO (NO) will now be displayed.
Use the or arrow button to change the NO to a
YES and then press ENTER.
• UNIT TEST and Y1 ON FAN ON will now be
displayed. The variable speed indoor blower will then
be turned on by the IFC for 10 seconds and then off.
• Furnace will then transition to the ignition sequence.
STAGE OFF will now be displayed. After a 45
second heat fan on delay, Stage 1 will be displayed
and 40% (low) heat inducer speed will be energized
for 10 seconds.
• Stage 2 will be displayed and 100% (high) heat
inducer speed will be energized for 10 seconds.
• The control transitions to off.
• The Model and Serial Number will be displayed.
• The variable speed indoor blower will now operate
for the heat exchanger cool down cycle and then
shut off at the end of the cycle.
• The comfort control can now be returned to the
homeowner's desired settings.
B) GAS VALVE SETUP (MANIFOLD PRESSURE
ADJUSTMENT)
NOTE: To obtain an accurate manifold pressure
measurement ,the manifold pressure must be
referenced to the burner box, since the burner
box pressure tap equalizes the gas valve pressure
regulator. To do so, install a tee and section of
tube (field supplied) in the tubing between the
tee coming from the burner box tube and the
will now be displayed.
Gas Valves
gas valve manifold pressure measurement fitting.
This tube and tee is in addition to the tube
attached to the gas valve pressure tap on the
outlet side of the gas valve. See Figure 58.
NOTE: In order to properly set the manifold gas
pressure, the incoming line gas pressure should
be tested with the unit off and again with the
unit operating at the high heat setting to ensure
adequate fuel supply to the furnace. The incoming
gas pressure should be 5" W.C. minimum and
13.8" W.C. maximum for natural gas.
Step 1
Before Setting Manifold Gas Pressure
Setting the manifold gas pressures is critical for the
correct operation of this furnace.
Before entering the Gas Valve Setup mode:
a. Turn comfort control system switch to the OFF
position and fan switch to the AUTO position.
b. Prime the furnace condensate trap.
Any call for heat or fan by the comfort control will
abort or cancel the Gas Valve Setup mode. The unit
will stay in Gas Valve Setup mode for a maximum
of 20 minutes.
c. Connect dual port manometer & field tubing per
Figure 39.
Note: MIN = 40% (low) heat, MAX = 100% (high)
heat
Step 2
Setting "MIN" Manifold Gas Pressure
To enter the Gas Valve Setup mode:
a. Scroll down on the user interface to Unit Test.
GF - D 15