UH1-DH1-SF-1L
Service Facts
21
Disconnect
electrical power to
furnace
Remove, clean,
and reassemble
burners.
Push RED reset
on both rollout
switches
Cycle power to
furnace and call
for heat
Ignition occurs
Do all burners
ignite within 5
seconds?
Is LP gas being
used?
NO
Is the burner orifice
size 56? Or matched
to Installers Guide for
LP?
YES
Install correct size
orifices
Check operation
NO
YES
Check burner alignment
Correct as needed
Check operation
Check flue pipe for correct sizing
and long horizontal runs or slope
less than ¼” per linear foot.
Correct as needed
NO
Is flue piping
restricted?
Correct as needed
Check operation
YES
Are flames from
burners impinging
on sides of heat
exchanger?
NO
YES
When fan
comes on, do
flames stay
consistent?
Replace heat
exchanger
Check operation
NO
Replace Roll out
switch
Check operation
YES
DEFINITION:
Limit switches are safety
devices that will open when an
abnormal high temperature has
been sensed.
REMOVE ALL JUMPER
WIRING TO SWITCHES!
Under no circumstances, shall
these switches be left
jumpered when not
troubleshooting.
YES
Are all burner flames
directed into heat exchanger
with a tight pattern?
(inadequately aired burners
tend to roll back)
NO
NO
Check combustion air
blower, venting, heat
exchanger for blockage
(i.e. sooting)
YES
4 Flash Fault LED
Is a Manual Reset, Flame
Rollout Switch open?
YES
Downflow Models
only:
Is this a downflow
*DH1 model?
Are the burner
orifice size 48
for NG?
YES
YES
Install correct size
orifices
Check operation
NO
YES
Summary of Contents for DH1B040A9241C Series
Page 6: ...6 UH1 DH1 SF 1L Service Facts continued on next page WIRING DIAGRAM From Dwg D345803P01 Rev A...
Page 7: ...UH1 DH1 SF 1L Service Facts 7 SCHEMATIC DIAGRAM From Dwg D345803P01 Rev A...
Page 8: ...8 UH1 DH1 SF 1L Service Facts continued on next page WIRING DIAGRAM From Dwg D345804P01 Rev A...
Page 9: ...UH1 DH1 SF 1L Service Facts 9 SCHEMATIC DIAGRAM From D345804P01 Rev A...
Page 18: ...18 UH1 DH1 SF 1L Service Facts...