Trane ADHMB060BCV3VA, Service Facts

Page: 40 / 54

40 UHM-DHM-SF-1H
Service Facts
2 Flash Fault LED
User Interface
shows a
RETRY LO?
(Lock-Out)
User Interface
shows a
RECYCLE LO?
(Lock-Out)
Scroll through
User Interface to
View number 1 of
Last 4 Faults
Cycle power to
furnace and call
for heat
Does gas
ignite?
Is outlet gas
pressure
~1.5"WC NG
~4.5 “WC LP?
YES
Do all burners
ignite within 5
seconds?
Check ignitor
position and
correct if needed.
Check operation
Refer to Installer Guide
for gas valve pressure
set up procedure
NO
NO
YES
Measure flame
current. Is flame
current less than 1
micro-amp?
(3-4 ua = Normal)
YES
Is flame sensor
located
correctly?
Replace flame
sensor. Check
operation
YES
Correct and check
operation
NO
Flame sensor is
good
NO
Is minimum
outlet gas
manifold
pressure
maintained? See
Installers Guide
for specification
Successful trial for
ignition occurs
Does inlet gas
pressure drop
more than 2"
WC
NO
Correct inlet gas
pressure
Check operation
Turn Low Heat
adjustment screw
one turn CCW.
YES
Is inlet gas
pressure above
14" WC?
Correct inlet gas
pressure
Check operation
YES
Connect differential
manometer per
Installer’s Guide to
measure manifold
pressure
YES
DEFINITION
RETRY LO = 3 unsuccessful tries for ignition
within a single call for heat
Flame has never been sensed
RECYCLE LO = 10 recycles within a single
call for heat.
Flame is sensed & then lost
For CORRECT
positioning of the
igniter and flame
sensor, see figure
on next page
Connect manometer to read
incoming gas pressure
Is inlet gas
pressure above
14" WC?
NO
Correct inlet gas
pressure
Check operation
YES
Note inlet gas
pressure.
Make call for heat
NO
Turn Comfort
Control to OFF
position
NO
Connect
differential
manometer per
Installer’s Guide
NO
YES
Clean and align
burners correctly.
Check operation
Connect manometer to read
incoming gas pressure
Turn Comfort
Control to Heat
and raise set-point
If all burners
continue to not
light, check
manifold pressure
per Installers
Guide
Check operation and set
manifold pressures per Installer
Guide