Trane UHMB060ACV3VA Series Service Facts page 11

UNIT TEST MODE
A) SIMPLE
Note:
Stage 1 = 40% (low) heat, Stage 2 = 100% (high) heat
A qualified technician can cycle the Variable
Speed Indoor Blower and the Modulating Gas
Furnace through its operation at the User
Interface.
•
The unit test cycle is entered at the user
interface.
•
The test cycle can only be entered when the
comfort control has no demand and the furnace
IFC is not reporting a fault.
fort control to the Off position and turn
the fan control to Auto. This will ensure
the unit test cycle will not be interrupted.
• Scroll down using the 6button at the user
interface until the display reads:
•
UNIT TEST. Press the Enter button.
• UNIT TEST and 3NO (NO) 4will now be
displayed. Use the 3 or 4 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 3 or 4 arrow button to
change the NO to a YES and then press ENTER.
•
UNIT TEST and Y1 ON FAN ON will now be dis-
played.The variable speed indoor blower will then
be turned on by the IFC for 10 seconds and
off.
•
Furnace will then transition to the ignition se-
quence. 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 in-
ducer 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.
UHM-DHM-SF-1H
B) GAS VALVE SETUP (MANIFOLD PRESSURE AD-
JUSTMENT)
NOTE: To obtain an accurate manifold pressure
measurement ,the manifold pressure must be refer-
enced to the burner box, since the burner box pres-
sure 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 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 7.
NOTE: In order to properly set the manifold gas
pressure, the incoming line gas pressure should be
Turn the com-
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 pres-
sure should be 5" W.C. minimum and 13.8" W.C.
maximum for natural gas.
Before Setting Manifold Gas Pressure
1)
Setting the manifold gas pressures is critical for the
Before entering the Gas Valve Setup mode:
a. Turn comfort control system switch to the OFF
b. Prime the furnace condensate trap.
Any call for heat or fan by the comfort control will abort
then
c.
Note: MIN = 40% (low) heat, MAX = 100% (high) heat
Setting Manifold Gas Pressure
2) Setting "MIN" manifold gas pressure
To enter the Gas Valve Setup mode:
a. Scroll down on the user interface to Unit Test.
b. Scroll to the right and select "Gas Val Setup".
c.
d. Select "MIN" and push the Enter button.
e. When asked "Are You Sure", select Yes, and push
f.
g. If pressure switch 1 & 2 learning routines have not
Service Facts
correct operation of this furnace.
position and fan switch to the AUTO position.
or cancel the Gas Valve Setup mode. The unit will
stay in Gas Valve Setup mode for a maximum of 20
minutes.
Connect dual port manometer & field tubing per
Figure 6.
Push the Enter button.
the Enter button.
The furnace will now begin the ignition sequence.
been performed; after successful ignition, the
inducer will go through this operation. (see Inducer
Learning Routine section).
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