506230−01 05/09
Page 22
Appendix A. Flow Diagrams and Wiring Diagrams
MIN
MID
MAX
YES
NO
YES
NO
Is indoor
temp. > 2ºF below
cooling set point
?
Is
indoor temp.
greater than the heat
setpoint plus the cool
setpoint divided by 2?
Is indoor
temperature > 2ºF
above heating set
point
?
YES
YES
NO
NO
NO
NO
YES
ONE OR
BOTH TRUE
NEITHER
IS TRUE
Is
there a cooling
demand
?
Is
there a
dehumidification
demand
?
DEACTIVATE ALL
EQUIPMENT
RUN EQUIPMENT IN
NORMAL HEATING
MODE
RUN EQUIPMENT IN
NORMAL COOLING
MODE
Is
EITHER true:
outdoor temp. > 95ºF;
indoor temp. < 65ºF
?
Humiditrol Comfort
Adjust setting is:
RUN
HUMIDITROL
START
Is
there a heating
demand
?
YES
Figure 15. ComfortSense
®
Model L7742U Thermostat Operation with Humiditrol
®
EDA Enabled
LEGEND
HBSP − High Balance Set Point
LBSP − Low Balance Set Point
ODT − Outdoor Temperature
NOTES
LBSP and HBSP must not be set closer than 2ºF
2nd stage lock in temperature −20ºF to 75ºF (OFF)
Temperature
Operation
Heat Pump Heat Only
HBSP
Heat Pump or Gas/Oil Heat
LBSP
Gas/Oil Heat Only
Indoor heat
demand
?
YES
NO
Gas/oil
heat (non−HP)
demand (W1) or EM
heat demand
?
YES
NO
ODT above
LBSP +3
?
YES
Compress-
or speed 1 (Y1
only) ?
ODT
> stg2 (Y2)
lock in temp
?
NO
YES
HP
stage
demand
?
Stg1
Stg2
Energize Y1, B,
G and start
upstage timer
Energize Y1, Y2,
B, G and start
upstage timer
Indoor heat
demand
?
NO
YES
Upstage
timer expired
?
NO
2nd stage
demand
?
YES
YES
ODT
< LBSP − 3
?
NO
YES
NO
Indoor heat
demand
?
NO
YES
NO
3rd stage
demand
?
YES
YES
ODT
< LBSP − 3
?
NO
YES
NO
De−energize
Y1 or Y1&Y2,
and G
2nd stg
HP (Y2) or
Gas (W1)
?
A
ODT
< HBSP − 3 or
(if HBSP is
OFF)
?
W1
Y2
De−energize
W1 and W2
HEAT PUMP
LOCKOUT
Energize 1st
stage gas/oil heat
(W1) and start
upstage timer
Indoor heat
demand
?
Indoor heat
demand
?
Upstage timer
expired
?
Energize W2
4th
stage demand
or 2nd stage gas/oil
demand (W2)
?
NO
YES
YES
NO
NO
YES
NO
YES
NO
YES
NO
YES
NO
A
Upstage
timer expired
?
De−energize
Y1, Y2, G
START
Figure 16. Dual Fuel Flowchart
