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On-Board Link W951 Heat Pump (R to O)
On-board link W951 is a clippable connection between
terminals R and O on the integrated control. W951 must
be cut when the furnace is installed in applications which
include a heat pump unit and a thermostat which features
dual fuel use. If the link is left intact, terminal “O” will re
-
main energized eliminating the HEAT MODE in the heat
pump.
On-Board Link W915 2 Stage Compr (Y1 to Y2)
On-board link W915 is a clippable connection between
terminals Y1 and Y2 on the integrated control. W915 must
be cut if two-stage cooling will be used. If the Y1 to Y2 link
is not cut the outdoor unit will operate in second-stage
cooling only.
TABLE 10
OPERATING SEQUENCE
SL280V Non-Communicating Thermostat with Humidity Control Feature and Single-Speed Outdoor Unit
OPERATING SEQUENCE
SYSTEM DEMAND
SYSTEM RESPONSE
System
Condition
Step
Thermostat Demand
Relative Humidity
Compre
ssor
Blower
CFM
(cool)
Comments
Y1
O
G
W1
Status
D
NO CALL FOR DEHUMIDIFICATION
Normal Operation
1
On
On
On
Acceptable
24
VAC
High
100%
Compressor and
indoor blower follow
thermostat demand
BASIC MODE (only active on a Y1 thermostat demand)
Normal Operation
1
On
On
On
Acceptable
24
VAC
High
100%
CS7500 thermostat
energizes Y1 and de-
energizes D on a call
for de-humidification
Dehumidification
call
2
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
High
100%
Dehumidification
mode begins when
humidity is greater
than set point
Dehumidification
Call
2
On
On
On
Demand
0 VAC
High
70%*
Dehumidification
Call Only
1
On
On
On
Demand
0 VAC
High
70%*
CS7500 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 single stage outdoor unit. 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
CS7500 thermostat to use for this application - Y2081 4 heat / 2 cool
*Dehumidification blower speed is 70% of COOL speed for all units .
**In Precision mode, CS7500 thermostat will maintain room temperature up to 2 °F (1.2°C) cooler than room setting.
