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Table 10. CBX25UHV, Thermostat and Two‐Stage Outdoor Unit Operating Sequence
Operating Sequence
System
Condition
Step
NO CALL FOR DEHUMIDIFICATION
Normal Operation -
1
Y1
Normal Operation -
2
Y2
BASIC MODE (only active on a Y1 thermostat demand)
Normal Operation
1
Dehumidification
2
Call
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Operation
1
Dehumidification
2
call
Dehumidification
1
call ONLY
BASIC MODE (only active on a Y1 thermostat demand)
Normal Operation
1
Dehumidification
2
Call
PRECISION MODE (operates independent of a Y1 thermostat demand)
Normal Operation
1
Dehumidification
2
call
Dehumidification
1
call ONLY
Jumpers at indoor unit with a two-stage outdoor unit
With Condensing unit - Y2 and R to O
With Heat Pump - none
* During dehumidification, cooling air handler speed is as follows: 70% of COOL cfm for 018, 024, 030, 65% for 036, 60% for 042, 048 and 060 units.
** Thermostat will maintain the room temperature up to 2°F (1.2°C) cooler than the room thermostat setting in precision mode.
System Demand
Thermostat Demand
Y1
Y2
O
G
W1
W2
On
On
On
On
On
On
On
Room Thermostat Calls for First-Stage Cooling
On
On
On
On
On
On
On
On
On
On
On
On
On
On
On
On
On
On
Room Thermostat Calls for First- and Second-Stage Cooling
On
On
On
On
On
On
On
On
On
On
On
On
On
On
On
On
On
On
On
On
Relative Humidity
Com
Status
D
pressor
Acceptable
24 VAC
Low
Acceptable
24 VAC
High
Acceptable
24 VAC
Low
Demand
24 VAC
High
Acceptable
24 VAC
Low
Demand
0 VAC
High
Demand
0 VAC
High
Acceptable
24 VAC
High
Demand
0 VAC
High
Acceptable
24 VAC
High
Demand
0 VAC
High
Demand
0 VAC
High
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System Response
Air
Handler
CFM
(COOL)
Comments
70%
Compressor and indoor
air handler follow thermo
stat demand.
100%
70%
Thermostat energizes Y2
and de-energizes D on a
60%/65%
call for dehumidification.
70%*
70%
Dehumidification mode
begins when humidity is
60%/65%
greater than set point.
70%*
Thermostat will try to
maintain room humidity
60%/65%
setpoint by allowing the
70%*
room space to maintain a
cooler room thermostat
setpoint.**
100%
Thermostat energizes Y2
and de-energizes D on a
60%/65%
call for dehumidification
70%*
100%
Dehumidification mode
begins when humidity is
60%/65%
greater than set point
70%*
60%/65%
Thermostat will try to
70%*
maintain room humidity
setpoint by allowing the
room space to maintain a
cooler room thermostat
setpoint**
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