Appendix A. Flow Diagrams & Wiring Diagrams - Lennox ComfortSense L7742U Programming Manual

Appendix A. Flow Diagrams and Wiring Diagrams
ComfortSenset Model L7742U Thermostat / Humiditrol
RUN EQUIPMENT IN
NORMAL COOLING
MODE
RUN EQUIPMENT IN
NORMAL HEATING
MODE
DEACTIVATE ALL
EQUIPMENT
Figure 16. ComfortSenset Model L7742U Thermostat Operation with Humiditrol
Dual Fuel Flow Diagram
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)
OUTDOOR TEMPERATURE AND BALANCE POINTS
HEAT PUMP ONLY
HBSP
HEAT PUMP OR GAS/OIL HEAT
LBSP
GAS/OIL HEAT ONLY
NO
ODT
< LBSP − 3
YES
?
NO
ODT NO
< LBSP − 3
?
YES
NO
De−energize
Y1 or Y1&Y2,
and G
506180−01 09/08
START
Is
there a cooling
YES
demand
?
NO
Is
there a heating
YES
demand
?
NO
Is
there a
dehumidification
NO
demand
?
YES
Is
EITHER true:
ONE OR
outdoor temp. > 95ºF;
BOTH TRUE indoor temp. < 65ºF
?
De−energize
A
YES YES
YES
NO Upstage
2nd stage Indoor heat
timer expired
demand
?
?
ODT
YES NO
< HBSP − 3 or
(if HBSP is
OFF)
?
YES YES
NO Upstage
3rd stage
timer expired
demand
?
?
Figure 17. Dual Fuel Flowchart
®
EDA Logic Diagram
RUN
HUMIDITROL
MAX
MID
Humiditrol Comfort
Adjust setting is:
NEITHER
MIN
IS TRUE
NO
Indoor heat
demand
?
YES
Gas/oil
heat (non−HP)
demand (W1) or EM
heat demand
?
ODT above
LBSP +3
?
Compress-
or speed 1 (Y1
YES
only) ?
NO
ODT
Y1, Y2, G
> stg2 (Y2)
lock in temp
?
HP
Energize Y1, B, Stg1
stage
G and start
NO demand
upstage timer
?
demand
?
NO
YES
Indoor heat
demand
?
Page 18
Is indoor
YES
temperature > 2ºF
above heating set
point
?
NO
Is
indoor temp.
greater than the heat
YES
setpoint plus the cool
setpoint divided by 2?
NO
Is indoor
YES
temp. > 2ºF below
cooling set point
?
NO
®
START
De−energize
W1 and W2
YES
NO
NO
A
YES
2nd stg
W1
HP (Y2) or
Gas (W1)
?
Y2
NO
YES
YES
Stg2
Energize Y1, Y2,
B, G and start
upstage timer
NO
YES
EDA Enabled
HEAT PUMP
LOCKOUT
Energize 1st
stage gas/oil heat
(W1) and start
upstage timer
Indoor heat
demand
NO
?
YES
Upstage timer
expired
?
NO
4th
stage demand
or 2nd stage gas/oil
demand (W2)
?
YES
Energize W2
NO
Indoor heat
demand
?