Page 24
TABLE 13
OPERATING SEQUENCE
SL297UHNV, Non-Communicating Thermostat with Humidity Control Feature and Two-Speed Outdoor Unit
OPERATING
SEQUENCE
SYSTEM DEMAND
SYSTEM RESPONSE
System
Condition
Ste
p
Thermostat Demand
Relative Humidity
Compressor
Blower
CFM
(COOL)
Comments
Y1
Y2
O
G
W
1
W
2
Status
D
NO CALL FOR DEHUMIDIFICATION
Normal Opera
tion - Y1
1
On
On
On
Acceptable
24
VAC
Low
70%*
Compressor and indoor
blower follow thermostat
demand
Normal Opera
tion - 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 Opera
tion
1
On
On
On
Acceptable
24
VAC
Low
70%*
Thermostat energizes Y2
and de-energizes D on a
call for de-humidification
Dehumidification
Call
2
On
On
On
On
Demand
0
VAC
High
70%**
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Opera
tion
1
On
On
On
Acceptable
24
VAC
Low
70%*
Dehumidification mode
begins when humidity is
greater than set point
Dehumidification
call
2
On
On
On
On
Demand
0
VAC
High
70%**
Dehumidification
call ONLY
1
On
On
On
On
Demand
0
VAC
High
70%**
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 Opera
tion
1
On
On
On
On
Acceptable
24
VAC
High
100%
Thermostat energizes Y2
and de-energizes D on a
call for de-humidification
Dehumidification
Call
2
On
On
On
On
Demand
0
VAC
High
70%**
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Opera
tion
1
On
On
On
Acceptable
24
VAC
Low
70%*
Dehumidification mode
begins when humidity is
greater than set point
Dehumidification
call
2
On
On
On
On
Demand
0
VAC
High
70%**
Dehumidification
call ONLY
1
On
On
On
On
Demand
0
VAC
High
70%**
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
Use Dave Lennox ComfortSense
®
7500 thermostat Y2081 4 heat / 2 cool for this application.
*Normal operation first stage cooling blower speed is 70% COOL speed.
**Dehumidification blower speed is, reduced to 70% of COOL.
***In Precision mode, ComfortSense
®
7500 thermostat will maintain room temperature up to 2 °F (1.2°C) cooler than room setting.
