25
2.4.2. Heat Pump Heating Operation
De-energize
W1 & W2
@furnace
Discharge
air below
130ºF
?
Discharge
air above than
135ºF
?
Discharge
air above than
135ºF
?
Discharge
air 20ºF above
heating staging
jumper setting
?
Discharge
air below heating
staging jumper
setting
?
4-minute
minimum runtime
in 1st stage
completed
?
2-minute
minimum runtime
in 2nd stage
completed
?
sor stage; ramp indoor
ing jumper setting
Energize next heat stages
Multiple stages stage on
and off to maintain heating
staging jumper setting
5-minutes
since completion
of last heating
demand
?
HEATING
DEMAND
RECEIVED
Yes
No
No
Yes
No
Yes
Yes
No
Yes
No
No
Yes
No
Yes
No
Yes
No
Yes
Shutdown all
compressor stages
and electric heat
Yes
No
Monitor
discharge air
temperature
Monitor
discharge air
temperature
Heating
demand
satisfied
?
Heating
demand
satisfied
?
Yes
5 min
delay
complete
?
No
Continuous air
delivered to
calling zones
ORDER OF STAGING:
HP stg 1 (Y1)
HP stg 2 (Y2)
Elec strip stg 1 (W1)
Elec strip stg 2 (W2)
ture at which the heat pump/electric
heat is allowed to run is fixed at 135°F.
plied to a heat pump with electric heat,
the electric heat will be staged ON to
maintainthedischargeairtemperature
tion.
5
Shutdown
compressor
stages 1 and 2 and
blower fan
HEATING DEMAND
RECEIVED
2.4.3. Defrost Operations
Defrost
control detects
need for defrost
cycle
?
Yes
No
Yes
Harmony III
control energizes
all compressor
stages
Heat Pump
enters defrost
Defrost
completed
?
No
Yes
Harmony III control
de-energizes all
compressor stages - uses
auxiliary heat to complete
existing heat demand
Defrost
period exceeds
20 minutes
?
No
De-energize
all compressor
stages
Yes
No
NORMAL
HEAT PUMP
OPERATION
Heating
demand
satisfied
?
Dual Fuel
?
Yes
No
Harmony III
sends signal to
W1 at indoor unit
Defrost
Tempering
?
Yes
No
HP cycles W1 OFF at
90ºF and ON at 80ºF
during defrost cycle.
NORMAL HEAT
PUMP
OPERATION
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