Lennox icomfort Wi-Fi Setup Manual page 33

Shut down HP
Stg 1...Stg 2
YES
Operate HP
Stg 1...Stg 2
if
T'stat
outdoor
heat
temperature
YES
demand
is...
(See NOTE 2)
?
Operate FURN
YES
Shut down FURN
Stg1...Stg 2
NO
T'stat
heat
demand
?
FURN
heat
lockout
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
at or
below
LBP
Stg 1...Stg 2
Operate FURN
Stg 1...Stg 2
T'stat
heat
Heat
demand
? pump
NO lockout
Figure 35. 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 oper-
ate 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
demand NO
25ºF
?
YES
YES
NOTE 3 − If emergency heat is selected, Furnace is used.
T'stat
YES
heat
demand
?
NO
icomfort Wi-Fit 7−Day Programmable Communicating Thermostat
Page 33
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
LOCKOUT TEMPERATURE
FURN ONLY