Page 51
TABLE 21 
OPERATING SEQUENCE 
Non-Communicating Thermostat with Humidity Control Feature and Two-Speed Outdoor Unit
OPERATING 
SEQUENCE
SYSTEM DEMAND SYSTEM RESPONSE
System
Condition
Step
Thermostat Demand Relative Humidity
Compre 
ssor
Blower 
CFM 
(cool)
Comments
Y1 Y2 O G W1 W2 Status D
NO CALL FOR DEHUMIDIFICATION
Normal Operation 
Y1
1 On On On Acceptable
24 
VAC
Low 70%
Compressor and indoor 
blower follow thermostat 
demand
Normal Operation 
Y2
2 On On On On Acceptable
24 
VAC
High 100%
ROOM THERMOSTAT CALLS FOR FIRST STAGE COOLING
BASIC MODE (only active on a Y1 thermostat demand)
Normal Operation 1 On On On Acceptable
24 
VAC
Low 70%
ComfortSense® 7500 
thermostat energizes Y1 
and de-energizes D on a 
call for de-humidication
Dehumidication 
call
2 On On On On Demand
0 
VAC
High 70%
PRECISION MODE (operates independent of a Y1 demand)
Normal Operation 1 On On On Acceptable
24 
VAC
Low 70%
Dehumidication mode 
begins when humidity is 
greater than set point
Dehumidication 
Call
2 On On On On Demand
0 
VAC
High 70%
Dehumidication 
Call Only
1 On On On On Demand
0 
VAC
High 70%
ComfortSense® 7500 
thermostat will try to 
maintain room humidity 
setpoint by allowing the 
room space to maintain 
a cooler room thermostat 
setpoint**
ROOM THERMOSTAT CALLS FOR FIRST AND SECOND STAGE COOLING
BASIC MODE (only active on a Y1 thermostat demand)
Normal Operation 1 On On On On Acceptable
24 
VAC
High 100%
ComfortSense® 7500 
thermostat energizes Y2 
and de-energizes D on a 
call for de-humidication
Dehumidication 
Call
2 On On On On Demand
0 
VAC
High 70%
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Operation 1 On On On Acceptable
24 
VAC
Low 70%
Dehumidication mode 
begins when humidity is 
greater than set point
Dehumidication 
Call
2 On On On On Demand
0 
VAC
High 70%
Dehumidication 
Call ONLY
1 On On On On Demand
0 
VAC
High 70%
ComfortSense® 7500 
thermostat will try to 
maintain room humidity 
setpoint by allowing the 
room space to maintain 
a cooler room thermostat 
setpoint***
Jumpers at indoor unit with a two stage outdoor unit
Cut factory jumper from Y1 to Y2 or cut W915 (Y1 to Y2)
With Condensing unit - Cut W914 (R to DS) on SureLight® control
With Heat Pump - Cut W914 (R to DS) & W951 (R to O) on SureLight® control
Dave Lennox ComfortSense® 7000 thermostat to use for this application - Y2081 4 heat / 2 cool
*Normal operation rst stage cooling blower speed is 70% COOL speed.
**Dehumidication blower speed is, reduced to 70% of COOL.
***In Precision mode, ComfortSense® 7000 thermostat will maintain room temperature up to 2 °F (1.2°C) cooler than room setting.