Page 19
31-5000734 Rev. 0
Operating Sequence
System Demand
System Response
System Condition
Step
Thermostat Demand
Relative Humidity
Compressor
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%*
Thermostat energizes Y1 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 demand)
Normal Operation
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 Operation
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 Operation
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
*Normal operation first stage cooling blower speed is 70% COOL speed.
**Dehumidification blower speed is, reduced to 70% of COOL.
***In Precision mode, thermostat will maintain room temperature up to 2 °F (1.2°C) cooler than room setting.
Table 12. Operating Sequence
NF80XV, Thermostat with Humidity Control Feature and Two-Speed Outdoor Unit
