Lennox Harmony III Installation Instructions

DUAL FUEL
Page 50
505023M 08/11
TroubleshootingDual Fuel Operation (Above Balance Point
REFER TO DISCHARGE AIR
UPPER LIMIT DIAGRAM
(Page 49) FOR UPPER LIMIT
AND DIFFERENTIAL DETAILS.
Energize W1
@ furnace
(see NOTE)
No
De−energize
all heat pump
and furnace
stages
Discharge
air falls to
130°F
?
Yes
Yes
No
Yes
BLOWER
SHUTDOWN
Heating
demand
satisfied
?
Yes
Yes
No
No
Yes
No
Energize 1st &/or 2nd stage
compressor(s) & Ramp in-
door blower to cooling stag-
ing jumper setting
Discharge
air below heating
staging jumper
setting
?
20−minute
minimum runtime
completed
?
No
No
No
Yes
De−energize all com-
pressor stages; start
5−minute delay
Shutdown all
compressor
stages
Yes
NOTE − On energize W1 furnace,
compressor heat is locked out − all
heat calls for the next three hours
use gas heat only
Yes
HEATING
DEMAND
RECEIVED
5−min
lapse since-
completion of last
heating
demand
?
Yes
Ambient
temp. Above
Balance Point
sensor setpoint
?
Yes
No
No
See Below Balance Point
sensor setpoint flow diagram
(Page 48)
Monitor
discharge air
temperature
Shutdown all
heating stages
Continuous air
delivered to
calling zones
Yes
No
No
Heat pump
locked out
(see NOTE)
?
YesNo
Monitor
discharge air
temperature
5 min delay
complete
?
Yes N o
System
in 3−hr backup
heat mode
?
Yes
No
Discharge
air DAS above
135°F
?
3−minute
minimum runtime
completed
?
Is
discharge
air at upper
limit
?
Does
discharge air
temp. meet
heating staging
differential
?
Heating
demand
satisfied
?
Yes
5 min
delay
complete
?
Heating
demand
satisfied
?
No

Lennox Harmony III Specifications

General

Brand	Lennox
Model	Harmony III
Category	Control Systems
Language	English