Lennox Harmony III Installation Instructions

DUAL FUEL
Page 48
505023M 08/11
TroubleshootingDual Fuel Operation (Below Balance Point)
REFER TO DISCHARGE AIR
UPPER LIMIT DIAGRAM
(Page 49) FOR UPPER LIMIT
AND DIFFERENTIAL DETAILS.
Energize W1
@ furnace; Ramp
indoor blower to
minimum CFM
setting
Discharge
air below heating
staging jumper
setting
?
Ramp indoor
blower to
heating staging
jumper setting
3−Minutes
minimum run time
in 1st stage
completed
?
3−Minutes
minimum run time
in 2nd stage
completed
?
No
Yes
No
Yes
Yes
Discharge
air falls to
130°F
?
Yes
No
No
No
Yes
No
Yes
HEATING
DEMAND
RECEIVED
3−Minutes
since completion
of last heating
demand
?
Yes
Ambient
temp. Below
Balance Point
Sensor setpoint
?
Yes
No
No
See Above Balance
Point Sensor
setpoint flow diagram
(Page 50).
BLOWER
SHUTDOWN
Yes
No
Yes
No
Yes
No
De−energize
W2
Monitor dis-
charge air
temperature
Energize W2
@ furnace
Monitor dis-
charge air
temperature
De−energize
W1 @ furnace
Hold dampers
open for 3½
minutes
Discharge
air (DAS) above
100°F
?
No
Yes
Yes
No
Is
discharge
air at upper
limit
?
De−energize
W1 & W2
@ furnace
Is
discharge
air at upper
limit
?
Does
discharge air
temp. meet
heating staging
differential
?
Heating
demand
satisfied
?
Heating
demand
satisfied
?
Heating
demand
satisfied
?
Yes
5 min
delay
complete
?
No
Continuous air
delivered to
calling zones

Lennox Harmony III Specifications

General

Brand	Lennox
Model	Harmony III
Category	Control Systems
Language	English