Lennox Harmony III Installation Instructions

GENERAL
Page 15
HARMONY IIIT ZONE CONTROL SYSTEM
System Flow Diagrams
Shutdown
compressor
stage 1 or 2
Continuous air
delivered to
calling zones
Discharge
air 7°F or more
above cooling
staging jumper
setting
?
4−minute
minimum runtime
in 1st stage
completed
?
5 minutes
since completion
of last cooling
demand
?
Shutdown compres-
sor stages 1 and 2
and blower fan
Ye s
No
Ye s
No
Ye s
No
No
Ye s
No
Ye s
No
Ye s
No
Ye s
No
COOLING
OPERATION
AC/HP
Discharge
air lower than
45°F
?
Monitor
discharge air
temperature
COOLING
DEMAND
RECEIVED
Discharge
air lower than
45°F
?
Energize stage 2
compressor and
ramp indoor
blower to
CFM setting
Energize stage 1
compressor and
ramp indoor
blower to
CFM setting
Monitor
discharge air
temperature
Discharge
air rises above
55°F
?
Cooling
demand
satisfied
?
Cooling
demand
satisfied
?
Discharge
air below cooling
staging jumper
setting
?
De−energize
stage 2
4−minute
minimum runtime
in 2nd stage
completed
?
Ye s
No
No
Ye s
Ye s
Shutdown all
stages com-
pressor /
electric heat
Continuous air
delivered to
calling zones
Discharge
air below heating
staging jumper
setting
?
4−minute
minimum
stage runtime
completed
?
5 minutes
since completion
of last heating
demand
?
Ye s
No
Ye s
No
No
Ye s
No
Ye s
No
Ye s
No
Ye s
No
HEATING
OPERATION
HP & Electric
Heat Strips
Discharge
air higher than
135°F
?
Monitor
discharge air
temperature
HEATING
DEMAND
RECEIVED
Discharge
air higher than
135°F
?
Energize heat strip
stage (W1/W2) and
ramp indoor blower to
CFM setting
Energize (Y1/Y2)
compressor heat
stage and ramp
indoor blower to
CFM setting
Monitor
discharge air
temperature
Discharge
air falls below
130°F
?
Was 2nd
stage (Y2)
running
?
Heating
demand
satisfied
?
Discharge
air 20°F or more
above heating
staging jumper
setting
?
De−energize
furnace W1 &
W2
2−mininute
minimum
stage runtime
completed
?
Ye s
No
No
Ye s
Ye s
Order of Staging:
HP stg 1 (Y1)
HP stg 2 (Y2)
Elec strip stg 1 (W1)
Elec strip stg 2 (W2)
Heating
demand
satisfied
?
No
Upstage
Was 2nd
stage (W2)
running
?
Ye s
Shutdown compres-
sor stages 1 and 2
and blower fan
Ye s
Ye s
No
No
Upstage

Lennox Harmony III Specifications

General

Brand	Lennox
Model	Harmony III
Category	Control Systems
Language	English