Lennox Harmony III User Manual

17
1.14. 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
?
Ye s
No
Ye s
No
Ye s
No
No
Ye s
No
Ye s
No
Ye s
No
Ye s
No
Discharge
air lower than
45°F
?
Monitor
discharge air
temperature
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
COOLING
DEMAND
RECEIVED
Shutdown compressor
stages 1 and 2 and
blower fan
Figure 15. Cooling Operations - AC/HP
Shutdown all
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
Discharge
air higher than
135°F
?
Monitor
discharge air
temperature
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-minute 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
Ye s
Ye s
No
No
Upstage
HEATING DEMAND
RECEIVED
Shutdown compressor
stages 1 and 2 and
blower fan
Figure 16. Heating Operation - HP and Electric Heat Strips

Lennox Harmony III Specifications

General

Brand	Lennox
Model	Harmony III
Category	Control Systems
Language	English