Dual Fuel Operation With Balance Points - Lennox iComfort Wi-Fi Setup Manual

YES
if
T'stat
outdoor
heat
temperature
YES
demand
is...
?
YES
Shut down FURN
®
iComfort Wi-Fi
Shut down HP
Stg 1...Stg 2
NO
T'stat
heat
demand
?
FURN
heat
Operate HP
lockout
Stg 1...Stg 2
at
HP stage(s) operate first;
or above
then FURN stage(s) (if
HBP
needed; see NOTE 1)
between
Operate HP
HBP and LBP
Stg 1...Stg 2
(See NOTE 2)
at or
below
LBP
Operate FURN
Stg 1...Stg 2
Operate FURN
Stg 1...Stg 2
T'stat
heat
Heat pump
demand
?
lockout
NO
Stg1...Stg 2
Figure 42. Dual Fuel Operation with Balance Points
Abbreviations:
FURN = auxiliary heat provided by gas furnace
HP = compressor heat
LBP = Low Balance Point
HBP = High Balance Point
T'stat = thermostat
NOTE 1 - Each Heat Pump and Furnace Heat stage will operate
until it meets the demand or until its stage timer lapses (20
minutes by default). If the timer lapses before the demand is
met, the system brings on the next stage in order of:
NOTE 2 - The chart below illustrates how the balance points
control whether HP or FURN will operate to provide heat.
50ºF
T'stat
heat
NO
demand
25ºF
?
YES
YES
NOTE 3 - If emergency heat is selected, Furnace is used.
T'stat
YES
heat
demand
?
NO
Page 37
HP-stg-1, HP-stg-2, FURN-stg-1, FURN-stg-2.
COMPRESSOR ONLY
HBP - FURNACE LOCKOUT
TEMPERATURE
EITHER COMPRESSOR OR
FURN HEAT
LBP - COMPRESSOR LOCK­
OUT TEMPERATURE
FURN ONLY
7-Day Programmable Communicating Thermostat